The cheapest and easiest thing to do would be to drag it to a tree, toss a small 1/4" rope over a branch high enuf to do the trick, tie up a pulley with a 3/8" rope thru it, then haul the deer up, back the truck or ATV in place, and load it that way. I've done that numerous times.
Even easier is to have two double pulleys and a longer rope to make a block and tackle arrangement. I put one of those together with 1/4" rope, and it works great. The block and tackle just takes a little more finesse to keep it from tangling, but it definitely takes less effort to lift a deer with it.
If you need some direction on how to make up the block and tackle, PM me...