I know that guy

Another item that makes a fantastic target stand are those stupid little corrugated plastic signs that can be found stuck in the ground at just about any intersection (or at about every third house in neighborhoods during elections). They can stand up to a surprising amount of abuse.

Around here, our local Code Enforcement Gestapo collects them up by the truckload and they store them in an outdoor locker for the owners to pick up if they want them back. After two weeks, they're heaved in the dumpster, at which point they're fair game.

If you go to Little Caesars, you get Target, Target...

Yeah, those yard signs work wonderfully. I work at a gas station and have gotten ahold of some of the old windmaster sign frames (the big cigarette signs you see in the yards). The sides are spring-clips and work great for holding cardboard or corrugated plastic. Add pushpins and a target and you're good to go.