Haha where do I start..
Buy the car/truck locally...best to get something here rather than on the net, so you can get sales support and actually look and feel the car/truck before you buy. Perth Hobby Centre in the city is the best and most competitively priced store IMHO.
Buy your spare parts online if your not in a hurry. eBay is good if your careful, but
www.towerhobbies.com is the best. I spent 20k with these guys over a few years, and managed to get prices that beat local prices on spare parts by half most of the time.
Do you want off or on-road? Get a brand that is well recognised, because not only will quality be better, but parts support is great also.
Best thing to do is jump on a few forums.
www.radiocontrolzone.com is a good one, and a good local forum is
www.teamadrenaline.net
Go to the hobby store and have a look. See whats on offer, and do take the advice of the people working there. They don't get commission from sales, and most of them are racers/enthusiasts themselves, and will most of the time recommend what is good and not what makes the most money for the store.
Once you've done that, post your results here and I'll tell you if the options they've given you (or you've found for yourself) are good or bad. Not tooting my own horn or anything, but RC cars were my obsession for many years and I know whats good and whats not through experience, having owned around 50 different vehicles, both electric and nitro, and I dabbled in a bit of RC racing also. I've mainly gotten out of it now, but I still have my workbench and array of tools and spare parts, in case I do ever want to get back into it.