Free: Contests & Raffles.
Don't waste your money on one of those things. I had one, and even added a wire extention to keep it open when it got some empties in it, and it was still more trouble than it was worth. I took a small flap of thin leather and sewed some lengths of small bungee cord into one end so I could loop the cords around and onto the knobs on my scope mount. the flap hangs over the ejection port and deflects the empties down. They pile up under the legs of the bipod, and I don't have to look for them in the sagebrush 6 feet away.
the one im thinkin of cost 10 bucks
Brother in laws works great.