I did it myself. Supplies cost about $350 (all from Home Depot, Rust-oleum epoxy shield, make sure to get the clear top coat as well.) Took a few hours of labor and about 1 week to complete (2 hours first night, dry for 2-3 days then one hour for the clear coat, then dry a few days.)
I had to borrow a pressure washer.
I did it 2 years ago and till looks great.
* 2-car garage