I use a 55 gal blue plastic drum. I haul it to town and fill it occasionally. In 1 hole, I have a male quick connect air chuck. In the other hole, I have a 3/4" neoprene hose that reaches 1" from the bottom, and it fits on a nipple and an elbow. I have a 6' long hose on the elbow to fill the tractor.
Filling procedure is simple: I turn my air compressor regulator down to 2-3 PSI. I hook the filler hose in the tank opening, turn the tractor key on to read the fuel gage. I then chuck up the air hose and watch the gage. It fills very fast with the 3/4" hose. When the gage shows just over 3/4 full, I pop the air chuck off. The residual pressure fills it within an inch or so of the top.
Cost? About $10 for fittings, clamps, and hose. Filling tractor without spills, priceless!