Quote from traderharley:
Do you think buy ask price is the same as buy market price?
NFLX is a very fast moving stock. Buy at Market and Buy with a Limit equal to the Ask are not the same. Which to choose depends on your trading style. For me, I would only use a Limit order to Buy because I want to specify the maximum price I'll pay not let someone else decide the maximum price I'll pay. If I want to be very aggressive, I'd make my Limit equal to or maybe even more than the Ask. If I don't want to be aggressive I'd set my limit equal to the Bid. If I want to be in between I'd choose limit price between the Bid and Ask.