Adaptive Pubs and Markets

In Brussels I saw a market where every price was displayed on a small lcd beneath the product, which also calculated the price per liter or kilogram. I imagine these were manually updated whenever the products were switched. Imagine if, instead, they were continuously updated as people bought or didn't buy the product. If fewer people were buying them, it'd be cheaper to encourage a purchase. The same idea, inverted, could be applied to pubs: instead of happy hour the prices would just go down as more people bought drinks.

The standard scheme (more demand yields higher prices) would encourage people to buy things they normally wouldn't, and browse for things that others might not have noticed. The inverted scheme (in the pub) would encourage people to bring friends and congregate at specific times.