I've got a nice walk in, but years before when my budget was smaller I purchased one of those glass door soda display coolers from a convenience store that as being remodeled for $50. It was about 6' wide, two doors, 30" deep and maybe 7' tall. Took all of the shelves out of it, installed some galvanized pipe hangar rods and had a dandy meat cooler. Could easily get four deer in it.
Noticed our local Pepsi distributer has a bunch of these sitting outside the warehouse. Bet you can still find them pretty cheap.