Up here in Canada, all prices are still in penny denominations but when you get to the register, and pay in cash, it is the cashiers job to round things up or down to the nearest nickel. If you pay electronically, you would still pay the sticker price down to the penny
Likewise in NZ, except that now, we don't even have 5-cent pieces any more - cash transactions are paid in 10-cent increments. Nobody cares.
Plenty of tedious detail can be found here : https://en.wikipedia.org/wiki/Cash_rounding