Cardboard Robotics

I teach high school robotics and we have been doing stuff with making cardboard robots. I give the kids in my class four gearhead motors, plastic sprockets, plastic chain, cardboard and glue sticks, axel stock and the rest is up to them. I guess if you got down to it they are not making robotics more like rovers. Right now they are tethered with cat5 cable. It is a tangled pain of a mess that is mediocre at best. Next year I want to move them to completely RC. However, I do not know what I need to buy to make this happen. From what I understand I need a radio, a receiver, and two motor controllers to do what I need to for each setup. Is that all that I need?

I have picked out the following for next year to make two setups:
Spektrum DX5e 5ch Radio x 2
Sabertooth 2X12 R/C Regenerative Dual Channel Motor Controller x 4

You would need a normal RC controller; this can control servo motors directly, and to control DC motors, you need an RC DC motor controller such as the Sabertooth. The Sabertooth is a dual motor controller which can control two motors, so you only need two of these if you want to control four motors separately. If you are using a 4WD setup (two motors on the left and two on the right), then you really only need one dual motor controller which can provide enough current for two motors per channel. If you have additional questions, do not hesitate to ask.