What to say when you don't want to reveal where you bought something?

Personally I would be proud to be wearing something that costs less than everybody, especially if it looks like any other dress others are wearing. I would be proud because they have foolishly wasted hundreds on something which is no more than a status symbol..what's the point in that? I would go the other way and say you bought for next to nothing on ebay, and say you really have more important things to spend your money on.