I bought a "quadrant target" after seeing one last year and have been quite pleased with it.
http://www.steelplinkers.com/Quadrant.htmlIt's made from heavy gage steel, and has withstood many shots. Seems to withstand even PCP energy levels. Took it to Ron Bradford's, and it seemed to be popular.
The bullseye at center swings on a longer (thin) arm, and the four quadrants surrounding the bullseye are more massive, so that when you hit one, they move but typically rock slowly.
If you hit dead center, the bull swings round several times rapidly, in a visually satisfying manner.
Put this target out there at 30 yards, and you can fire away. If you miss the bullseye, there is a visual indication that lasts a few seconds telling you if you are high, low, left or right.
Simple and durable. The company is a little enterprise by a laid off airgun hobbiest. I think this is worth $40.
I found this on a search, looks pretty cute. But the laziness factor of just putting that Steelplinkers target out, firing away, and just bringing back at the end of the session is very nice. I've left it outside on the back porch all winter, I just hit it with some WD40 every once in a while.
http://www.instructables.com/id/BB-Gun-Target/