Market= stocks filled instantly at current price, sometimes can be more or less then actual stock price. This is because you bought a stock being sold by another investor who is asking for a certain price. Example: You buy one stock at market price, currently priced $5, the order is filled and you see your stock, when purchased, was $4.92. You bought a stock someone was selling for $4.92.



Limit: You pick the price you are willing to pay for a stock, and the order is not filled unless a stock can be purchased at your LIMIT.