I did mine myself, my receipts look to total $381, but I had and was donated some stuff. The way I ran the wire, I ended up using about 96' of wire/tubing to get from main panel, through spa box, to flex, to main connect in the spa. I could have run it different, but didn't want to see the wiring from inside house. Main section was mounted to side of house, other area was trenched 24" below grade.
spa box - 75
main breaker - 9
wire = $.78/ft. I needed about 100' of 3 and 55' of white = 253
PVC is about 4.50 a stick so about 25$ there
Add connectors, clamps, elbows, solvent.
I had flex pipe and a bunch of little things (brackets, tools, some fittings, tapcons, paint for after), big help was a friend's business had a section of scrap wire that was just enough, so one wire less for me to buy.