Dont do it. Buy a quality car and quality stuff. If nothing else it will be worth more when you go to sell it if you dont like racing. Ive been down the rtr road before and it wasnt cheaper and it wasnt fun. There are reasons why cheap things are cheap. Cheap cars break easily and cheap engines run erratically.
Racing is tons of fun as long as your not constantly trying to put band aids on your gear. I can take getting whooped on the track with a big smile but when my car breaks and stuff goes wrong its not near as fun.
Buying used is a good alternative but before you buy I recommend a good inspection of the gear your buying.
Its also a good idea to go hang out at the track and LHS you plan to utilize for a bit before you buy anything. You may find its near impossible to get parts for car X but everyone and their brother has parts for car Y. If your just starting out this is probably the biggest factor you should consider when making a purchase. Nothing sucks more than breaking a part and waiting weeks for it to come in on backorder.
Money spent now can and will save money in the long run. If nothing else get an rtr like the 8ight or RC8 which are still mainstream cars that parts should be readily available for just about anywhere you go.