What is the difference between a market and limit order?
A market order will guarantee an execution of the order but does not guarantee the execution price. At times, it will not be surprising to get an execution price that is different from the market (current bid- current ask), especially if it is a fast market for that particular stock.
A limit order will guarantee an execution price or better, but it does not guarantee the execution of the order. For example: If you place an order to buy 200 shares of XYZ at $5.00 limit for the day, your order will not be executed until the stock trades at $5.00 or lower. Or If you place an order to sell 200 shares of XYZ at $5.00 limit for the day, your order will not be executed until the stock trades at $5.00 or higher.