Spend the extra $30 and get the 200 oz-in motors.
1) Yes you'll need a 24V to 40V, ~10 amp power supply, and a prallel port cable. The cable must have all the wires straight through. A lot of the ones you see at places like Best Buy won't work. But their only about $10. If you want, you can also hook up home and limit switches.
2) Never ben to Fry's( don't have them here), but you really shouldn't need anything else.
3) All you should need are the HobbyCNC instructions. it's really not that difficult. If your not sure about something, just ask here.