Thumbs
Any kind of shooting bench is better than trying to shoot off the sticks. I've got one word for you: Pricklypear. If you don't know what that is, goodle it. It's a cactus that covers most if not all of the prairie region of the U.S. If you're going to be shooting off your belly you better have a thick pad. And I won't even mention prairie rattlers.
If nothing else, buy you a small folding leg table or cut you a piece of plywood and buy a pair of the folding legs for about $20 and add them to the plywood. If all else fails you can shoot over your hood from sandbags, but put something on the hood to keep from burning the paint off. Shooting off the bipods sounds good, but trust me, it's not.