I’ve used, with good success, everything from old tarps, billboard tarp material, door mats, and carpet remnants. I stuff the stuff in feed bags, which cost 75 cents, or grass seed bags for smaller targets. This sort of thing stops a 635 grain arrow with 28% foc out of a 46 lb longbow. My broadhead target is stacked newspaper in a duct taped cardboard box. Works great. Gotta be cheap. Have fun. Dwc