I suppose the ethically correct answer would be to inform the store, but I've done this in the past and you would not BELIEVE the hassle it is to try to give them more money! Seriously, you think they would take you at your word and take your money, but it is a biggel hassle than getting your money back!
So when it has happened to me since then, I regard it as a happy error and don't contact the store. And I don't feel at all guilty.
So when it has happened to me since then, I regard it as a happy error and don't contact the store. And I don't feel at all guilty.