Law of supply and demand
From Simple English Wikipedia, the free encyclopedia
The Law of supply and demand describes how prices are related to the number of things available (supply), and the number of things people want (demand).
When there's less of something, people are usually willing to pay more. So shortages drives up prices. But when price goes up, suppliers start making more of it, "flooding" the market. They usually have to start lowering prices to get more buyers.
So "demand" drives up "supply", which pushes down "price".