This seems to be the age old question. Its not easy to answer not knowing your situation.
If you are starting from scratch, the Losi RTR is a good deal and will get you almost everything you need to get started. If you were running electric, and still have a radio and a couple decent servos laying around, I would search around for a kit, engine, and starter box that you could pick up at a good price. There's always some good deals on ebay or the forums. There is a list of things you'll need.
Kit
Engine
Pipe
Starter box
Radio and reciever battery
Servos
Glow igniter
I'm sure someone can add to what i may have missed.
Good Luck and welcome back..