Shasta is an off-brand soda product. They have cola, root beer, lemon-lime, all your classic off brands. I know you can get it in Maryland but I'm not sure about elsewhere. They tend to come in cans if I remember correctly (I neither buy nor drink the stuff).
Faygo is an off-brand diet soda. They have a large variety of flavors, some of which are just plain odd. Occassionally my dad buys them (for my mom I believe, but I really don't know, I just see 'em in the fridge). Shasta comes in glass bottles (well, they were glass last time I checked). Just like the glass bottles Pepsi and Coke came in (not the real old glass bottles, the ones that came before our current plastic bottles).
I have a feeling the FIRST logo will be on Shasta but that's just me. Maybe because I'm not too interested in Faygo.
If you want more information, do a search on Google for National Beverage Company.
Matt