I was at the gun shop recently and noticed a bi-pod made of two hunting arrow shafts. I had an idea that I havent put together just yet but I have two old aluminum arrow shafts that I will dip the fletching ends into some black "hand tool grip coating" a few times down about 4" and let dry.
Then drill a hole through both shafts just passed the coating and run a bolt through both so it can "scissor". A velcro strap can hold the bi-pod to the gun while waiting for varmints. Won't cost me much. It should look something like this when done: except legs wont shorten.