I have a set of 24"x24" pads made out of a white plastic like a cutting board they have ropes and fit in a bag that came with them. They are heavy but tough. One time I was stuck in the mud, I put them under the jacks on wet muddy grass and lifted the coach off the ground so I could put boards under the tires, they cupped a little but did not break and went back to normal after the pressure was removed. I still carry them in the coach but have not used anything since I put the SnapPads on. So nice not to have to get out and place them or get out and retrieve them. Here is a picture of the SnapPad setting on the wet grass lifting the rear tires off the ground.
Note it is a little deformed but took it like a champ.
Not what I would call cheap but very convenient.