I have made half a dozen or so of these. I used 30 gallon grease drums. The grease is in a plastic bladder so the drum is pretty clean when empty. The 1x1 inside to drum keeps it from getting out of round from the weight of feed and gives something to screw eye bolts into. The ones pictures have swingset chain but rope works fine too. the trick is put a spreader bar (conduit) that will allow you to get the top on & off easily and give something solid to attach a rope for hanging the feeder.
I have since bought some tripod leg kits and converted a few to freestanding since there isn't always a convenient limb to throw a rope over. I got the kits at BPS for $25 each, and bought 1 inch emt conduit for the legs.
Most of my feeders have the photocell triggered Moultrie slinger motors on them. They work great.