Not much, according to London Drugs. I had the misunderstanding that change had to be accepted, up to certain maximums that it's not excessive. In Canada this is:
- forty dollars if the denomination is two dollars or greater but does not exceed ten dollars;
- twenty-five dollars if the denomination is one dollar;
- ten dollars if the denomination is ten cents or greater but less than one dollar;
- five dollars if the denomination is five cents; and
- twenty-five cents if the denomination is one cent.
However the rule that supersedes these tender limits, according to the RCMP is that "The form of payment which is mutually acceptable to the parties to a transaction appears to us to be essentially a matter of private agreement between those parties. For example, a provider of goods or services could insist on payment by credit card or cheque."