Market, limit and stop-limit orders

A market order buys or sells immediately at the best available prices. It is fast but you accept slippage, especially in thin books.

A limit order sets the worst price you will accept. It rests in the order book until the market reaches it, and may fill partly or not at all.

A stop-limit order waits until a trigger price is touched, then places a limit order. The stop protects against a move; the limit controls the price you accept after the trigger.