I have had radio control cars since my early teens and my first full RC car was a Tamiya Rough Rider which in its day was a work of art and based on a 1/10th replica of the full size dune buggies raced in America.
The hobby itself can be great for introducing all ages to construction, setting up and eventually racing whether it is indoors or outside, if you are looking at getting inot this for the first time there are many options to look at which have been covered before in other guides so I won't go over them again. Basically you need to look at the initial cost of the model and as always 'you get what you pay for' also look at the cost of spares and how easily they are available.
This hobby can be huge fun without huge cost if you want it to be, I would advise perhaps joining a local club in you area by looking at this site brca.org and this site is full of clubs within the UK. Joining a club will help you get the most out of your car and set up advice will be freely available.
You can race almost anything from 1/18th scale cars to 1/5th monsters but generally the bigger the scale the bigger the bills for spares. I would possibly advise to start of with something electric as they are simple to use clean and go as fast as nitro cars without the hassle. for a beginner or for someone wanting a simple but fantastic form of racing in the UK, then the Mardave 'V12' Hot Rod or Banger Cars would be a fantastic starting point, the cars are simple to build and you can be competitively racing on the same day you build the car. The cars are based on 1/12th hot rods that race on circuits or ovals and these are normally indoors and the tracks are made from a special carpet that gives excellent grip to the foam tyres that are on the cars, they use a standard kit or Mabuchi 540 type motor and 4 cells nicads and you have the option of inexpensive hop up parts such as electronic speed controllers, different tyre compounds etc.
The kits start at around £54.00 and the spares are pocket money prices for example full set of wheels £3.25, tyres £2.25 per pair, body shell £4.50 and a new motor is only £5.50 and all this is manufactured in Great Britain and available direct from mardaveracing.com under the V12 brand.Mardave even run thier own race club in Leicester on monday nights( details on Mardave web site)