I've been happy with this:
It's a full scale IPSC silhouette minus the D zone with overall dimension of 12" x 24" The bullseye in the center is 5" in diameter backed by a 6" plate hung on the back of the main plate.
The two orange brackets are from Gear Head Works ($40) and they slip into normal 1" EMT conduit that can be purchased in 10' lengths for about $6, for a total cost of $52 with an extra center tube.
I've used it like this with a single target, as well as with a 4" tube on top to hang a pair of steel targets or a steel target and a Coroplast target backer for paper targets. If you hang a target backer, you'll want to use guy lines to pull the bottom forward several inches to keep it from getting spattered by spall from the hits on the plate.
I stack the four 4' legs and the 2' or 4' top tube together, slip knot 550 cord over the ends and carry the tubing over my shoulder with the plate carried on a strap from the other shoulder. It's very portable and quick to set up and take down.