Before you start this project there are some options for the flooring to consider:
Epoxy Floor Covering
The preparation work for this popular solution is vital. If you don't get up all the grease and dirt the epoxy won't stick. This is a heavy-duty coating that comes in two parts that have to be mixed. It costs approximately $240 to do a two-car garage, and it takes at least two days to dry.
PVC Floor Tiles
The easy way out is to use interlocking PVC floor tiles that lay right over the existing floor. You don't need any special tools or adhesives. The only tool you'll need is a saw to trim the edges. The floor tiles/panels come in a variety of colors as well.