I have several like that and use plastic 55 gallon drums. Works fine.
You don't need concrete around the pole. Just a 3 foot deep hole. Water the soil when you back fill around the pole and let it set before loading the feeder. Cheap 1.5" or 2" wide / 8' long ratchet straps from Harbor Freight work fine and last for years.
The only downside is you need a ladder to fill the feeder (the top of mine are about eight feet above ground level}. Either a six foot A-Frame ladder next to the feeder, or and eight foot straight ladder leaning against the pole works.