The main economic influence that determines prices is: the stock market. interest rates. government spending. supply and demand.

The correct answer is : Supply and demand

a Product's price will most likely to increase if more consumers demanded that product. And a product's price will most likely to drop if no one want it.

A product's price will increase if only a few people could supply it (which mean that it's hard to obtain), and a product's price will decrease if it could be obtain easily (a lot of people could supply it)