Transactions on credit/debit cards are not rounded so it's rarely an issue these days when even corner stores are not handling much cash.

Also, the rounding algorithm is in the article you linked to:

> If the price ends in a one, two, six, or seven it gets rounded down to 0 or 5; and rounded up if it ends in three, four, eight or nine.

That tends to work out pretty even for consumer/store if you are buying groups of randomly priced items.