DIY air leveling bags

I built a pair of these when the instructions first came out and I followed the instructions to the letter. At the time, I had a dual axle fifth wheel with a GVWR of 7800lbs. I now use them with my truck camper which weighs 2300 lbs, on an F250 SRW (I know, I'm overweight), but back to the air bags. I've never had a problem. They do what I need them to do, and have done so for years. I can tell you this; you won't build two of them for $100 if you have to buy all your materials at today's prices. It will be considerably more. BTW, I don't like to lay them directly on the ground because of potential puncture problems. Trimmed down 18 wheeler mudflaps under the bags eliminate this worry.