I have made two different type targets.
For one get two 2x6 boards and two all-thread rods. Drill holes about two inches from each end in the middle.Cut and lay strips of cardboard in the middle of the boards, when you have enough tighten the all thread to sandwich the cardboard between the two pieces of wood. You can add two more pieces or wood at the bottom to form a T shape to keep from falling over.
The other is a bag target, with a seed sac from the local feed store. Stuff it with rags then staple it shut.
Both work ok but keep them out of the rain.