As for flooring just get with a local carpet place and ask them nicely if you could get somethin they are tearing out. You can usually get this sort of thing for free although you may have to go to the job to get it. I do this and I love it. I get a 12 X 12 or so about once a year and just flop her down. You can easily move it under the table your workin at. Once it gets too nasty to look at, (oil spills etc) just cut it into easy to handle strips and set it out for the garbage man or burn it. (I live in the country so I burn mine)

Be careful about building tables for your garage that will set in the middle. You may want to pull a car in there someday or somethin like that. I just set a sheet of particle board on my table saw. When I want to clear the garage for a different project I stand the board up along the wall ond roll my saw to the side.
Benches along the walls can be anything ya want.

In the pic you can see the carpet under the left corner of saw table. I have it placed under another small folding table in the back corner. I have a few smaller pieces that I move around when Im workin at the saw table they just weren't laying where you can see them when I took the pic.