I have made my broadhead target from the foam you can buy at home depot. I used a sheet of the 2' X 8' and cut it into 2 X 2 with layers of a woven astroturf (fake grass) between the layers. The foam is 2" thick and after the astroturf layers and a couple layers of duct tape around the whole thing it is about 9" thick and weighs around 5 lbs. Total cost was under 40$. If you used two 4 X 8 sheets and made a 4' X 4' target (You better not miss that!

) im sure you could do it for under a hundred bucks.
I have shot hundreds of shots with my crossbow at close to 330 fps and have only needed to refresh it once with a new coat of duct tape and a 5$ can of spray foam insulation. Hmm.....the more i think about this the more i want to make my own.
Rolln.