I just ran across a TERRIFIC website where you can create your own target designs, in PDF, and then print them. It's not only easy to do, but the extra bonus is that it's free. Check out printtargets.net.
Neat. Not trying to upstage yer thread, but I use old political yard signs. Most these days have wire stands and are made of weather resistant corrugated plastic. And, after the election they are free and you are doing everyone a favor by pulling them. (be sure the candidate does not want to save them for future elections, they are expensive, $4.00 to $5.00 each). And, if you do not like political people they can be fun to shoot at.
Rifleman1776, I buy metal spike tipped plastic posts made to hold electric fencing wires which are sold at farm supply stores. They are taller and more durable than the political signs. They're about 40" tall and the multiple wire holders on them allow for placement of cardboard backers at several heights. Very inexpensive, to boot.