The deadline to use the old one pound coin is at midnight on Sunday.
From 16 October the round £1 coin will no longer be legal tender, as it is replaced by the new pound coin.
However, some shops including Tesco, Poundland and Aldi, have said that they will still accept the old coin for a bit longer.
Some people have complained that businesses are still giving out the old coins as change.
The group Which?, who look after the rights of shoppers, have said that people shouldn't accept the old coins as change after Sunday and to ask for new ones.
Banks are also encouraging customers to return their old coins as soon as possible.