Legal tender

[NeverUseThisName]

I'm trying to explain the concept of money to my 10yo (how cash is a representation of the value of an exchange) and he has asked me a question I cannot answer:

Say you buy a sweet, hand over your cash, and eat the sweet. The seller then rejects your payment even though it is legal tender. What happens then?

You shouldn’t eat the sweet as the transaction isn’t completed (he hasn’t accepted your money) but also, why wouldn’t he accept your money if it’s legal tender?

You're in debt to the seller

Yes, you’re in debt and still owe payment for the sweet.

How do you know he has or has not accepted your money?

Ask for a receipt

Well you know because the seller would tell you he rejects your money otherwise he would say thank you very much. Either way if you've eaten his sweet before completing payment you're in debt to them.

How often do you buy, say, street food and get a receipt? Granted, if you wave a £50 and they say “I can’t change that”, then they have clearly and reasonably rejected the method of payment, and the buyer needs to find another way of paying.

But say they take the correct money from you, turn around and go to their cashbox - how are you to know they’ve not accepted the money? How are you to know the transaction is not complete?

They have to have a reasonable period to check that what you have given them is what they asked for. In just the same way, if you handed over £5 in small tender coins, you couldn't assume the goods were yours till they had had a chance to count the money.