^^Pay is subjective to location. In Ontario, PTers start at Min Wage which is currently $8.75/hour. Assistant Managers were starting out at $11.00/hour but is negotiable based on experience with the company and or management (and I know the start rate went up with the last min wage increase as well but I don't know how much) Store managers start at $30,000 a year (they are salary) but again like an Assistant is negotiable based on experience with the company or management. I make quite a bit more then that as I've worked for the company since 1997, and have been a store manager for almost 2 years now and Assistant for 3 years prior. (though I did leave the company for almost 2 years between 2000 & 2002).
I couldn't tell you what the rates are in other Provinces or States.
Likewise age restriction is also based on Location.
In Canada the law states you must be at least 16 to work. However due to the enforcement of the ESRB ratings the law also states that you must be old enough to buy what you sell. So in Canada you have to be 19 to buy beer so you have to be at least 19 to sell it. So likewise since you have to be at least 17 to buy an M rated game, by law you have to be at least 17 to sell it and work for EB Games/Gamestop in Canada.
Again I can't speak for the US as each State I know has there own laws.
Finally as the age thing at least in my part of Canada we are not usually looking for students anyways. We usually need people who can work any hours. Which usually means post High School. But the thing is with how the company opperates most stores have more then enough people who can work evenings and weekends. They need people who can work days, open etc.
I get a lot of high school kids telling me they want to work for me but there availablity is always weekends and evenings. I personally am currently over staffed anyways, but all my guys are available evenings and weekends. What I need is people who can open in the morning on a weekday. (though I'm personally good in that area right now too)