> A stock goes up when someone buys it and down when someone sells it. this isn't true: to buy a share someone else has to sell it (with some exceptions) in r

> A stock goes up when someone buys it and down when someone sells it. this isn't true: to buy a share someone else has to sell it (with some exceptions) in reality the price depends on what the buyer and seller agree (electronically or otherwise) -- just like everything else you buy in general if demand is higher than supply the price rises, just like other markets