Personally, I have a few Word Doc's I created, that I print, and tape to cardboard, usually, the LARGE Priority Mail boxes, they're cheap, abundant supply, and store easily, and provide a nice area to tape on, or use the Shoot-N-See's. I can usually tape 2 8.5x11's side by side far enough to shoot multiples, and get some practice moving from target to target.
I print up mainly an 8" circle colored kind of light off yellow (buff) like a manilla folder, and will put a 1 or 2" black dot in the middle. They're not as dark as an IDPA target, and provide an easy reference point with the dot. The 8" circle just happens to be the A-Zone, so for me, it works great.
Personally, The best steel re-actives are probably spinners, as they don't require a trip downrange to reset.