I have run it all day during school. Your fine because there is a limit of 10 items per day so it wont look like your autobuying because you wont have bought like 200 items xD
For a starter program, definitely worth getting. Profit will depend on your list, and how long you run it for.
A lot of random things, and I do recomend getting the Igloo AB, awesome program and super low risk. Here's Lightning's list: