Ha!  That reminds me of my shopoholic (and also fat) SIL who used that logic to land in bankruptcy court thrice so far, reasoning (tee-hee) that that the more shit she bought on sale, the more she saved, and of course she bought most of the shit which she didn't need on credit.  Because "it's on saaaale and gotta get it now in as many colors/sizes/stock-up quantities so I don't pay full-price later!!!"  Jesus.