How are stock fill prices determined?

Let's say Joe puts down a sell order (when no buy orders exist) for $5.00. Bob then puts up a buy order at $10.00. How much does Bob pay?

Shawn has a buy order (when no sell orders exist) at $100.00. Jim then lists his stock for sale at $80.00. Does the stock order fill at $100.00, or $80.00?

Sorry for the simple question, I haven't found it answered elsewhere.

Submitted July 14, 2017 at 03:03AM by dr1nfinite http://ift.tt/2tltoDI