Lots....

With the money I've spend on broken parts, worn tires and wheels, gas & rechargeable batteries in the past three months I could have probably bought a 2nd car.

Granted, I've become a much better driver and my parts breakage has gone down a little but things still happen. A lot of your expenses will depend on how hard you drive, how often you drive and the conditions you drive in.

If you go out once or twice a week for an hour or so each time and only drive on open fields your extra expenses will be minimal. If you drive in rough terrain around lots of trees and spend a lot of time jumping expect your expenses to go up considerably.

It's all fun, but can get expensive.