recently, i freind of mine gotten (what i believe) is a Traxxas T-maxx and it needs a receiver and a crystal. in addition to the receiver and crustal, would i need to buy another control for the truck? and how much would the receiver cost?

check out towerhobbies.com for al different types of recievers.

If your friend does not have a controller then you would need to buy one of them also. If you are going to need to buy both the reciever and transmitter(+ crystals) then check ebay. You could get all of them for cheap.