I think everybody is taking the OP a little too seriously.
If you buy something at a store and the next day it goes on sale, what harm is there in taking a shot and seeing if they'll give it to you at the sale price? I really don't think the OP was that upset about it. Hence the
at the end of the post and the mild joke about guil over using coupon codes.
If I'm wrong, then I apologize for interrupting.