My recommendation is "Don't do it" until you have some experience buying and selling options. "At the money" option prices can have huge volatility and it's extremely easy to get stopped out by a sudden movement in the underlying share price. Instead, you should set yourself a mental stop, and physically place the order to close out the option when your target stop price is hit. If you don't have the time to track the underlying stock during the day and are concerned that you might miss the opportunity to close out your position before the price goes against you, then I would avoid short term "at the money"options altogether. Instead, just buy the underlying stock that you like and sell a covered call against it.