If you have any kind of feed store close by or an Agway (something of that nature) you could get an old feed bag and stuff it full of rags, old screening, plastic bags from the grocery store or something of that nature. Stuff it pretty tight and close it up.

Same bag packed with the polyester filling from some old bed pillows can work. Just remember it's gotta be stuffed pretty tight. Old blankets stuffed into the bag.

Lots of things.