I use an Ames pillow target on a PVC frame in my basement. It has been down there about 16 years and is stuffed with sheets of 6 mil plastic drop cloths. I don't shoot at the vitals much and pick random spots to shoot at like eyeballs, the tip of the tail and others to keep from wearing a spot out. The target is double sided as well. Unfortunately these targets are no longer made but a large coffee back would be the same.
The target is bigger than the picture would suggest, it is about 36" X 30".