As far as where to buy here in the states, I use RDQ, and GetFPV for most all of my purchases.
FPV Drone - Racing Drone Store - FPV Racing Quadcopter
FPV Drones for Sale, Quadcopters, Racing Drones, Motors and FPV Goggles | GetFPV
I have bought some parts, motors, ect on Ebay...
As for a radio, my suggestion would be the Radiomaster T16S. A Crossfire module can be mounted in the back bay.
RadioMaster TX16S Multi-Protocol RF Module OpenTX 2.4GHz RC Transmitter w/ Hall GimbalsDefault Title
