A few of these look like a hoot !! 12 Fun Plinking Targets that Won't Break the Bank - Guns & Ammo
One of my Fav's not on the list is the plastic Easter eggs. Fill one side up with white flour and tape the 2 sides together.
The week after Easter I always hit the local Kroger and buy 5 or 6 bags of the plastic eggs.
Makes a big white explosion with hit with a 5.56 AR..
You guys should try chalk, for chalk line reels. Comes in a variety of colors, and it's fairly inexpensive.Old prescription bottles work for this exact same thing. Fill them with flour. You can also usually get various sizes and set up targets that are S,M,L,XL on the same range using the bottles.