Liquidators mark it up to mark it down
What you tend to get is a lot of marketing hype, tacky "EVERYTHING MUST GO" signs -- and prices that are actually higher than you might have seen before the "sale." The way it works is this: Liquidation companies acquire the inventory from the often-bankrupt parent company and then look to make as much money as they can selling it. This often means marking the prices up to full retail before marking them back down -- but often they aren't marked down as much as they were prior to the sale, and the liquidators hope to profit from naive consumers who assume that "sale" means "bargains."
The video below is from late last year but with the economy continuing to sour, there will likely be many more going under sales hitting your town. Caveat emptor.