Market is both a noun and a verb that have to do with selling. Companies that successfully market potato chips make people buy a big bag at the market.
Are you in the market for a new pair of jeans? That means you are looking to buy. You might be the market, or likely customers, for a certain brand. The cost of those jeans will be whatever the market can bear, meaning the most profit that can be made, either by selling fewer pairs at high cost or lots of pairs at a lower cost. But if you buy them on the so-called black market, you might get a bargain price — only to find your new jeans aren't authentic — knock-offs of the real thing.