Basically, trading means buying and selling an asset. And if you want to do that, you need to place an order. The term “order” refers here to how you will enter and exit a market.
On CEX.IO Exchange, you can use basic and the most popular order types — market and limit. More advanced order types are available on CEX.IO Broker.
A Market order (instant order) involves buying or selling cryptocurrency immediately at the best available price. For example, on the BTC/USD market, buying crypto with a market order means selecting the amount of quoted currency (USD) to spend (i.e. "buy me enough bitcoins for $100 right this moment"). Selling with a market order means selecting the amount of base currency (BTC) to sell.
The market price for an order is calculated from the top of the order book. For example, you would like to sell 5 BTC with a market order. There are currently buy orders for 3 BTC at $50,000, and 4 BTC at $49,500, which represent the best available prices. Your market order will match the first one completely, giving you $150,000 for 3 BTC, and the second one partially with $99,000 for 2 BTC. In total — $249,000 with an average price of $49,800 per BTC.
Market order is executed instantly in most cases (only a complete absence of orders in the order book will leave it hanging) and cannot be reversed.
A Limit order is placed to buy cryptocurrency below the market or sell it above the market at a certain price. Execution of this order type is not guaranteed until a requested price matches the opposite order from another user. Until full execution, the order may be canceled by the user at any time.
These orders may be partially completed if there is currently not sufficient volume at a matching price to cover the entire order. The remainder of the order will be left open until closed by another matching order. The remainder of the order may be canceled as well, returning the remainder to the user's balance.
The executed part of fiat or crypto involved in limit order may not be reversed or returned.
Please note that each market has its minimum amount for placing an order.