Veteran traders have told me that market orders for options are literally last resorts to be used for all out panic, like you need money to post bail immediately kind of panic, and that some kind of limit order is best because someone is guaranteed to scalp your money with a market order. But it sure stings when you miss out on tons of gain by buying manually. Algos can prevent that, but then, you're an algo trader and that's a whole 'nother level.