Horse stall mat. I get em at Tractor Supply for about forty bucks. Half inch thick (maybe more than that) heavy duty rubber. Cost about forty bucks. Should stop anything from any bow made. Probably crossbow bolts as well. Only drawback is the weight. I'd figure close to 100 pounds. I built a frame out of PVC pipe and it's more than paid for itself in potential lost arrows so far.
Old gym mat will work as well, pulling broadheads out though is doable but sort of a pain in ass. Bonus points if you can get a used one prior to them tossing them out.