Do it yourself, watch you tube videos, I did mine in one hour, they tell u exactly how, and what.
Cost under $100.
List, 14.50 box at home depot $50. Roll of 8.3 wire 25, double 50 amp breaker 25. Your HD might more or less .
Quick , decide on close place to breaker box, wire outlet box, mount it, run wire to CB box . Turn off main house power, if you can pull meter do it. Install breaker, run red wire to one side, black to other side, green and white go to same bus.
This is not rocket science, very easy if breaker box is in garage.
Good luck.