Monk, I used the Behr one-part epoxy from Home Depot to start with, so I've stuck with it. About $24 a gallon. The RustOleum two-part epoxy from HD is $58 a gallon, with a cleaner/degreaser and paint sprinkles. I'd use that if I started over. One gallon should cover your garage. The paint sprinkles are nice, as they will help to hide tire marks and oils spots, which are inevitable. For clearcoat, I'm using the Behr 910 clear epoxy, same price, $24 a gallon. It goes a long way, enough for several coats. The milkiness comes from over-application, I think, or trying to put a second coat on too soon. Just be careful to apply thin coats of the clear, let them dry a full day before applying the second coat.
I'm using Armstrong VCT (vinyl composite tile), from HD, sold in packages of 45 for $28. A package will cover 45 square feet. I'm going to use black and white with color flecks, on the advice of some smart guys who've done this before. I'll use Henry's 750 adhesive, about $20 a gallon, which will be plenty. I'll use a bit of red tile for a kind of border. The b&w tiles are usually in stock; the red is special order. You'll probably need 15 packages, so with tax that's goig to be about $450, plus $20 for adhesive. That's a bit more than fifty cents a square foot, but not bad. I'm only doing my workbench area in the tiles, about 120 square feet. The rest is the gray epoxy with the terrazo look from the color sprinkles. It looks great so far, by the way.