The hammer rang once. A spark jumped off the anvil and did not go out. It waited. They followed.

It was a wet Saturday in February, the kind where the rain does not fall so much as hang about. Tara stood under the bus shelter on the corner of the Green with her phone in both hands and read the message again.

Hi Tara, sorry, Mr G is fully booked now until the 7th of March. Shall I put you down for then? Best, Carol, Gale's Driving School.

The seventh of March was three weeks away.

Her driving test was on the twelfth of June. She had booked it in December, the first date she could get, and she had been pleased with herself for booking it so early. Next September she would be going away, if she got in somewhere, and she wanted to be able to drive before she went. Her mum's car was old and slow and smelled of dog, and Tara loved it.

In the autumn she had paid for a block of ten lessons with Mr Gale. Ten lessons for three hundred and fifty pounds, which was thirty-five pounds a lesson instead of the thirty-eight it cost to pay one at a time. Her dad had paid half, as an early birthday present. She had paid the other half from her Saturday money, the money that was not for the deposit.

She had had four lessons. Mr Gale was patient and kind and called everyone young lady or young man, whatever their age. He had taught her to move off, and to stop, and to turn left without mounting the kerb. But every lesson since Christmas had been at least a fortnight after the one before, and every time she started again she seemed to have forgotten half of what she had learned. She had not yet been on a roundabout. She had not yet driven in the rain.

Six lessons left. Three weeks until the next one.

She put her phone away and went into the café to think.

"I was going to say I'll just wait," Tara said.

She had put her phone on the back table, with Carol's message showing. Danya was there, sorting a box of old board-game pieces into piles by colour, for reasons he had not explained. Across from him sat Fee, who had once paid a fee to leave a phone contract early and still talked about it. Fee read every set of terms and conditions now, all the way to the end, and had a habit of turning to the last page first.

"I've paid for six more lessons," Tara said. "That's two hundred and ten pounds. If I leave Mr Gale now, I waste all of it. Two hundred and ten pounds of my dad's money and mine, just gone. So I'll wait. I'll book the seventh of March and then the next one and the next one, and I'll use them up."

It felt good. It felt responsible. Her dad always said you didn't waste money you had already paid.

Fee did not answer straight away. Fee picked up Tara's phone and scrolled up past Carol's message to the booking confirmation from the autumn.

"What does it cost to leave?" said Fee. "Not what you've paid. What it actually costs you, if you leave today. Price the exit before you decide anything. You've worked out what it costs to stay, sort of. You haven't worked out the other one."

"It costs two hundred and ten pounds," said Tara. "That's the whole problem."

"Does it?" said Fee. "Who told you that?"

"Says who that it doesn't?" said Danya, without looking up from a pile of red counters.

"Nobody, yet," said Fee. "That's the point. She's guessed. The fee is there to keep you, usually. I want to see how big it is before she decides it's everything."

Tara opened her mouth. Then she shut it again.

"How do we know what it costs?" Danya asked.

Nobody knew. That was the problem.

Cancel came in at eleven, shaking a wet umbrella in the doorway and getting told off for it. Cancel had read every gym contract in town and two of the bus company's. Cancel refused to cry wolf about any of them. Cancel said most contracts were fair, and that the trick was knowing which bits weren't.

Tara showed Cancel the message and the confirmation.

"How do you actually get out?" Cancel asked. "There'll be a page. There's always a page. Notice period, deadline, cost."

The confirmation email had a link at the bottom: Our terms. Tara tapped it. It opened a page on the driving school's website, plain and short, with twelve numbered paragraphs. Cancel read it over her shoulder, slowly, all the way down.

Paragraph nine said:

Block bookings. Lessons in a block are paid in advance at the block rate. Unused lessons may be refunded on request, less an administration fee of £30. Refunds are paid within 14 days.

"There," said Cancel. "That's it. A fair exit isn't a red flag. That's a fair one."

"I don't get it," said Tara. "What does it mean, unused lessons?"

"The ones you haven't had," said Cancel. "You paid for ten. Ten at thirty-five is three hundred and fifty. You've had four. So you've got six left, and six at thirty-five is two hundred and ten. Notice period, deadline, cost: there isn't a notice period, there isn't a deadline, and the cost is thirty pounds. They keep thirty and give you back the rest."

"Show me the source, then," said Danya. "How much is the rest?"

"Two hundred and ten, take away thirty," said Cancel. "A hundred and eighty pounds. Back in your account in two weeks."

Tara stared at the paragraph.

"So leaving doesn't cost two hundred and ten," she said slowly.

"Leaving early is the expensive part, usually," said Fee. "Not this time. Add the fee to the total and the total is thirty pounds."

"Who checked that it's really that simple?" said Danya.

"I read it all the way down," said Cancel. "Twice. It's that simple."

Marcus came in with three envelopes held together by a bulldog clip. Marcus kept all his money in envelopes, labelled in thick marker pen. Bus. Lunches. Mum's birthday. Not yet. He said it was old-fashioned and that it worked. He had a fourth envelope today, with nothing written on it.

He read the message and paragraph nine and nodded.

"What's the money for?" Marcus asked. "You've got two lots of money here and you're treating them as one. Give every pound a job."

He took two of his envelopes out of the clip, tipped the contents into his coat pocket, and laid the empty envelopes on the table side by side. On the first he wrote GONE. On the second he wrote STILL TO COME.

"The four lessons you've had," said Marcus. "Four at thirty-five is a hundred and forty pounds. Where does that go?"

"Gone," said Tara.

"Gone whatever you do," said Marcus. "If you stay with Mr Gale, it's gone. If you leave tomorrow, it's gone. You had those lessons. You learned to move off and stop and turn left. That's what you bought with it, and you've got it. It doesn't come back, and it doesn't make you stay. It's not in this decision at all."

He pushed the GONE envelope to the side of the table, out of the way.

"Now the other one. Write the plan before the money comes. What's still to come?"

"Six lessons," said Tara.

"Six lessons, two ways," said Marcus. "Way one: you stay with Mr Gale. You get nothing back and you pay nothing more. Way two: you take the hundred and eighty back and you go to someone else. Who?"

"Juno's instructor," said Tara. "Ms Achebe. Juno passed first time. She's thirty-eight a lesson, one at a time."

"How much do you actually need? Six at thirty-eight," said Marcus. He did it on the back of the envelope. "Two hundred and twenty-eight. You'd have a hundred and eighty back. So switching costs you forty-eight pounds more than staying."

He wrote £48 on the STILL TO COME envelope and put down the pen.

"Forty-eight pounds," said Tara. "Not two hundred and ten."

"Not two hundred and ten," said Marcus. "Two hundred and ten was never the question. It just felt like it."

Devon arrived last, as he usually did, with a library book under his arm and his coat buttoned wrong. Devon answered almost every offer with a question about Sundays. He said everything cost you something, even when it was free, and the trick was to say out loud what you were giving up.

He listened to the whole story without interrupting. Then he picked up the STILL TO COME envelope and turned it over.

"What does it cost you?" Devon asked. "You've got the money. Forty-eight pounds. Now say what you'd be swapping. What's the next-best thing you'd give up, either way?"

"If I switch, I give up forty-eight pounds," said Tara.

"And if you stay?" said Devon. "Not in money. In Sundays. In weeks."

Tara thought about it. "Time," she said. "Mr Gale's next slot is in three weeks. He's been doing one every fortnight since Christmas."

"Then do the sum," said Devon.

Danya did it, counting on red counters. Six lessons, one every two weeks. "Twelve weeks," he said. "From the seventh of March. That's the end of May."

"And the test is the twelfth of June," said Tara. "So I'd have my last lesson about two weeks before the test, and the ones before that would be a fortnight apart, and every time I'd forget half of it."

"And Ms Achebe?" said Devon.

"Juno says she does weekly," said Tara. "Six weeks. I'd be done by Easter, and I could have some practice with Mum after."

"Every yes is a no to something," said Devon. "Staying says no to forty-eight pounds of spending and yes to twelve weeks. Switching says yes to forty-eight pounds and no to waiting. How much is forty-eight pounds to you?"

Tara knew that one exactly. She did seven and a half paid hours on a Saturday at the bakery, at eight pounds fifty. "A Saturday is sixty-three pounds seventy-five," she said. "So it's less than one Saturday."

"Less than one Saturday, against six weeks," said Devon. "I'm not saying which is right. I'm saying that's the swap. The two hundred and ten pounds isn't in it anywhere."

"Hm," said Tara. "So it's the waiting I'd be paying for, if I stay."

"Every yes is a no to something," said Devon again, and smiled. "That's all I ever say."

They did not decide anything straight away. Tara wanted to hear from the people it affected first, and so at half past twelve she rang her dad, and then she rang Mr Gale, and then Juno came in out of the rain because Tara had texted her.

Her dad was at the garage, waiting for his tyres to be done.

"Don't chop and change," he said. "I've seen people do it. Every new instructor spends a lesson finding out what you can do, and that's thirty-eight pounds for a lesson where you learn nothing. Mr Gale knows you. He's cheap, and he's good, and you paid him. Finish what you started. That's what I'd do."

It was the strongest version of his argument, and he had a point about the first lesson.

Mr Gale himself answered on the second ring. He sounded tired and sorry.

"I know, young lady, I know," he said. "February to June is my busy time, everybody wants to pass before the summer. I'm sorry about the gaps. I really am. But I'll tell you this. I've been teaching thirty-one years, and I've never had a pupil fail who did their lessons with me and practised in between. If you want your money back, it's in the terms, and Carol will do it, no hard feelings. But I'd like to see you through."

Tara believed him. That made it harder, not easier.

Juno had come in with wet hair and a takeaway cup.

"Ms Achebe's brilliant," said Juno. "She did me every Tuesday, same time, for two months. By the end I could do roundabouts in my sleep. But I don't know if she's got any slots. She's busy too. And she's stricter. She made me cry once, about mirrors."

"How do we know she's better, though?" said Danya. "Juno passed. Mr Gale says everyone passes. That's two people saying their one's good."

"Let me listen first," Tara said, when Juno started to argue with Danya on Ms Achebe's behalf.

She had thought, that morning, that the question was whether to waste two hundred and ten pounds. It had felt like a question with one sensible answer, the careful answer, and she had been pleased to have found it so quickly. Now the two hundred and ten pounds had turned into thirty, and then into forty-eight, and it was not even the most important number. The most important number was twelve weeks against six. And there were things nobody could put a number on. Whether Mr Gale would get her through. Whether Ms Achebe had a slot. Whether her dad would mind.

She looked at Marcus's envelope pushed off to the side of the table, the one marked GONE.

"I think we missed someone," Tara said. "Me, in June. I was only thinking about me in the autumn, when I paid."

She opened her email and found the confirmation from Gale's Driving School. At the bottom it said Reply to Carol. She tapped it. The reply box opened, white and empty, with the cursor blinking at the top.

On the table in front of Tara were Marcus's two envelopes, one marked GONE and pushed aside, and one marked STILL TO COME with £48 on it. There was paragraph nine on her phone: less an administration fee of £30. There was Danya's row of red counters, twelve weeks long, and Devon's question, what does it cost you? There was her dad's voice saying finish what you started, and Mr Gale's saying I'd like to see you through, and Juno's saying every Tuesday, same time.

Her thumb hovered over the empty box.

 

 

(Write the line Tara sends to the driving school.)

 

The spark dimmed to a warm dot and settled back on the anvil. The Green was just the Green again.

Back on the Green

That afternoon Lan, who was seven, was halfway through a very long jigsaw of a lighthouse, and she was not enjoying it at all.

Danya asked her why she didn't stop. Lan said she had already done the whole sky, and that took ages, so she had to finish.

Danya asked whether doing the sky had been fun. Lan said no. It was all the same blue.

Danya asked whether the rest of it would be fun. Lan looked at the box and said the rest was all the same grey.

Lan thought about it for a long time. Then she put the lid back on the box and got out her paints, and said that the sky was done and it would still be done tomorrow.

Afterword. The idea in this case is the sunk cost. A sunk cost is money or time that has already been spent and cannot be got back, whatever you decide next. The four lessons Tara has had are a sunk cost: they are paid for and used, and they are the same whether she stays or goes. Because they cannot change, they do not belong in the decision, even though it feels as if leaving would "waste" them. What does belong in the decision is everything still ahead: what leaving really costs (here a £30 fee, not the £210 she feared), what each choice costs from now on, and what else each choice gives or takes away, such as weeks of waiting before a test. Read the exit before you assume it is expensive, split the money into what is gone and what is still to come, and say what you would be swapping. You can practise comparing what each choice costs from here on in LedgerQuest.