There are many options for doing your garage floor. If you are looking for a contractor, Tim Miller, known as "Tim the tool man" specializes in epoxy floors. He is quite busy, typically booked solid for a month or more.
I inspect many garages and can tell Tim's work easily. His floors typically look very nice.
I did my own floor in a garage addition I built....here it is;
I VERY MUCH suggest that whoever does this for you that you have them mix a cup of H&C "Shark Grip" to the clear coat. This is MUCH better than sand and will keep your floor from being slippery. It is an anti slip additive. It cost less than $5.00.......I do not know why most folks fail to use this. I am glad I used it.
Hope this helps!
Frank