Are they worth getting and how much roughly do they cost?

What kind of transmitter and receiver do you have installed in the car??

I have no idea it a kyosho inferno mp 7.5 sports 3, came ready built and can't find anything about the receiver and transmitter in manuals.

OK, it looks to me like you may have a Perfex KT3HS Transmitter. That transmits on 27 mHz. Unfortunately, i've never used this kind of radio, so i can't walk you through the settings. You should however be able to control the throttle/brake settings with a function button on the transmitter. I would say to you, either read the manual for the radio, or wait till your man gets home, or anyone with experience with the car, and can help you out. If it's brand new and out of the box, I would think it's only going to be a transmitter adjustment issue rather than a throttle/brake linkage problem.

Oh and YES! Failsafe is important. Nothing worse that watching your car going at full throttle towards that big group of kids watching you play....and there's NOTHING you can do about it.

I highly recommend upgrading that $10.00 radio to something more substantial with a built in fail safe, like a Spektrum, Futaba, Airtronic, etc.

You have a very decent little car there. Do it justice and get a decent radio for it.

Fair enough, currently fixing the dalek anyhow cheers.

A fail safe is important. You should also get a throttle return spring. A new radio is not a bad idea but not an immediate need. The failsafe and throttle return spring are must haves. A run away buggy can do some major damage to someone. A failsafe is around $20., and a throttle return spring is around $2. The return spring is good incase you lose power to the receiver and or failsafe.