You can buy them online if you have to. Just so you know, MH systems cost around $150, and HPS costs around $200. For a dorm room grow, you might want to stick with fluoros. They are cheaper, cooler, and safer.

By the way, I don't suggest growing in a dorm room. Everyone in your hall is going to smell it once it starts flowering. The fire department does random searches during fire drills. Your roomate IS going to find out (not sure if you're trying to keep it secret). When I lived in a dorm room, I started a plant in my room, and moved it to a good location outside once it was a foot tall.

peace