[RMcNeal]

We have Good Sam and KOA. Both give us value for different reasons. Good Sam gives 10% at any participating parks, which we seldom use, but we also get discount at the CW/Gander store and discounts at certain fuel stations. KOA we use for overnight stops when travelling. Their discounts are OK, but points accumulate and you will get free nights here and there depending on use. Membership for both is minimal each year.
We also have a GA State Parks membership, which is free to join. It gives us a free night based on accumulated points as well. I've had it for about 6 years now and have gotten money back at several trips. Since we live in FL and travel north regularly, it gives us value. If you are not on the east coast, it may not be worth it, but many other states have a rewards program too. Don't overlook these as it is usually free and the value comes with frequent use.