I applied online. The process took 1 week. I interviewed at GameStop
Interview
Was very straight forward. Filled out an application, told an employee (whom I interacted with frequently when purchasing products), and was called to schedule a single interview. After the interview I got the job and started within a week or two. Wanted to make sure I understood the MSRB and knew not to advertise or sell M rated games to minors.
Straightforward. Come in for interview. They will give you a call with an offer. If you have general knowledge of games, you will be fine. If you have knowledge on game accessories, that is plus.