I (my mother) made mine. I got some waterproof fabric (looks like tyvek) and plastic beads from the fabric store. Drew up a template that was similar in shape to an Armageddon Gear Xwing, cut the fabric, sewed it up leaving a corner open, flipped it inside out like a sock, then filled it up. Put a length of paracord in the corner in a loop, and sewed it shut. I had enough to make a couple bags for under $10 and it took longer to buy the stuff than to do it. My mom really got into it. It's not often that I come to her with something I'm lost on, and she is an expert.