if you just want a target backstop for field point arrows...ONLY... then it's simple.... use rags.
there are a couple of styles.
1. fill up a burlap or feed sack bag with cut up rags, which makes it easy to carry around.
2. build a 4 ft x 4 ft frame with treated 2x6 boards, and cover the front and back sides with chicken wire. Stand it up and fill the entire area with old clothes or cut up rags, by stuffing them down from the top... before you place the top board on. The top board is really best when it's faced with a 2x4 on the top front and back, so that the top is open for allowing more rags to be stuffed down as the whole target area expands with shots, as the rags shift downward a little bit over time. Then put cardboard across the front, for attaching targets. The back can be left open or attach old carpet. The rags will pack up and stop the field points from passing through... and arrows can be pulled out with two fingers. It will last forever. Trust me on this one... I was a President of a 3D archery club for years.