I built a 450 quad, frame kit was $25.00, (4) ESC at $13.00, (4) motor set for $48.00, flight control CC3d for $18.00, PDB was $12.00. I did buy a go pro type camera for $80.00 with all sorts of mounts. I have not tried to put a GPS unit on it as I am just flying L.O.S. I have my Pixhawk with the gps, OSD, route flying, and all that. The Pixhawk setup was $180.00 then I had to build up another frame.
You will need to up your budget by double to get what you are looking for.
Buzz.