I bought a Garage Floor Coating kit that comes in a box at Home Depot. It comes in two colors - grey or tan. It comes with paint chips to scatter over the paint to give it a speckle paint look. No floor etching required. I simply cleaned the garage floor thoroughly with detergent, a scrub brush, and rinsed, allowed it to dry, then rolled on the coating and scattered the paint chips on every 6x6 area. Then let it dry for 1-2 days. It lasts 1-3 years before tire wear marks show up. I re-coat mine every 3 years just to keep it looking fresh. It takes about 3 kits to finish my extra deep 3 car garage. Each kit costs about $60. I even bought a grey speckled workbench to match the floor...
Jim