These are cheap, simple, and effective.
The one on the left is just a piece of 4-6" PVC pipe put in the ground like a post. It's called a "pig pipe". "A" is a board cut to fit the pipe, and work as a plug. "B" is ground level. "C" is a 3/4- 1" hole. I usually put them 14-18" deep, and make them about 5ft. tall.
The one on the right is made from 4" PVC pipe, and a "Y". Again, "A" is a board, and this one needs several holes drilled in it to let rainwater drain out. Hole "D" is for a rope. Just tie it on a tree, with the "Y" at about knee height. It can be as long as you want.
Both are capped off with a slip-off cap. It helps to either slot the top of the pipe with a saw, or sand the heck out of it, so the cap slips on & off easily.
I have used both of these for years. They are easily moved, simple, use no mechanisims or batteries, and require no maintenance. I have two electronic feeders that stay in the garage... Don't need the headache!.......Bug
P.S. I don't know why the line drawing is messed up, but it should be enough to give you the general idea.