Are you a current student? If so, I would exhaust all possible internship opportunities before signing on for door-to-door sales of "CD-ROMs and Books" for the summer. If an internship doesn't work out, you will probably make a loooot more money waiting tables, tending bar, working for movers, etc
If they're telling you about the potential for making lots of money, think about this: if you have the kind of charisma and intelligence to successfully sell "CD-ROMs and Books" door to door, think of how much more money you could make selling a product or service that people actually want.