A market order says buy, or sell, right now, at whatever the current price is. It guarantees execution — the order goes through — but not the price, which can shift in the moment it takes to process.
A limit order says buy, but only at this price or better. It guarantees the price if the order goes through at all; if the market never reaches your limit, you simply don't get a fill. A market order trades price certainty for a guaranteed trade; a limit order trades a guaranteed trade for price certainty.
A limit order protects your price — even when that means no trade at all.
Educational content only. It is not personal financial advice.