Buy Cells, Motors, tyres and tools new.
Everything else get from E-bay or the like.
If you're just starting and you want an Xray then an FK05 is as good as a T2 and half the price and will also probably come with spare parts. (Also by the time you're up to speed the T3 will be out (next Tuesday I believe
)) and you can buy that new.
Speed controls like a GTX will cost $80 or so, Radios will be $100 and just the same as new etc etc etc.