This is a rough price breakdown for my bot - its a 4WD invertible (I hope!) rammer so quite similar to what youre after:

Motors - 4 x 9.6V cordless drill motors - £40
Batteries - 4 x 7.2V Nicad packs - £20
Wheels - 4 x 75mm blue wheels - £22 (Although Id strongly recommend using 100mm blue wheels if you wanna be invertible - I managed it with the 75mm ones but vertical space is tight! Main bot chassis is only 50mm high!)
Speedos - 2 x Electronize 30A with external relays - £100 (15A microprocessor Electronizes are a cheaper option but only by about a tenner each)
Radio gear - 6ch Skysport - £120 (Technobots 4ch kit would be better though, and only £40)

Then theres the things you forget about at first:

Battery chargers for nicads - 2 x fastcharge units - £40
Miscellaneous nuts/bolts/screws etc - Could well possibly be up to £30 depending on how much you use.

So, going by the cheaper options Ive listed, youre looking at £255 give or take a bit, not including materials for chassis etc or any form of weapon. Thats the cheaper end of the scale anyway......

EDIT: Forgot about things like a removeable link, power light, failsafes, mixer etc - approx £35-£40 on top of that

(Message edited by K_C_R on April 25, 2007)