What is a market order?
A market order buys or sells immediately at the best available price. Buy orders fill at the ask; sell orders fill at the bid.
Placing a market order (MetaTrader example)
- Choose the symbol, for example EUR/USD.
- Open a New Order and select Market Execution.
- Enter the volume in lots, for example 0.01.
- Set a stop loss and, if you want, a take profit.
- Click Buy by Market or Sell by Market.
Always set the stop loss at the same time as you open the trade, not "later".
Slippage
In fast markets the price can move between your click and the fill. If you are filled at a different price from the one you saw, that is slippage. It is most common around news releases and at the weekly open.
Requotes
Some account types use "instant execution", where the broker may offer a new price (a requote) if the market has moved. Market execution accounts fill at the next available price instead.