Market vs limit orders (what they mean and when to use which)

A market order tells the system to buy or sell now at the best available price. It aims for speed and a full fill. The final price may be a little higher or lower than the last quote you saw, especially in fast-moving or thinly traded markets.

A limit order tells the system the maximum price you’re willing to pay to buy, or the minimum price you’re willing to accept to sell. The order will only execute at your limit price or better. This gives you price control, but it may take longer to fill or may not fill at all if the market never reaches your limit. Partial fills are possible.

Use a market order when execution is more important than the exact price (for example, highly liquid, widely traded shares during regular hours). Use a limit order when price matters (for example, around news, in pre/post-market, or for less liquid shares/ETFs). 

A quick example: if the best offer is €10.00 and the price is jumping, a market buy could fill at €10.06. With a €10.02 limit buy, you’ll only be filled at €10.02 or better, and if the price skips above €10.02 you won’t be filled. This is general information only.