A lot depends on where you are in this country. Out here, $25-30 is really high for a RV site in a campground, and we are often lower than that in RV parks. Usually $16-18 in a CG for electricity, water and a picnic table, whether state parks or COE campgrounds (and with senior pass, COE half of that).
We have a lot of municipal or county parks with RV parking to support one or two events, and at other times the needs of seasonal workers. I've paid $5 to $10 a night for those. Again, usually a parking space, electricity, and water. I know of one that is free for the first two nights, along the RR tracks south of Chanute.
I find that rates are pretty much the same no matter what is parked in a site, although many RV parks have several tiers of site prices, based mostly on size and facilities at the site (paved vs gravel pads, concrete patios vs grassy areas, etc). If you want to set up a eight foot PUP in a 80-foot pull-through deluxe patio site, rather than a 45 foot diesel pusher, you are going pay the same price for the site.
My experience is where land is mostly agricultural, $2000 to $10,000 an acre. Where land values go up to $200,000 to $10,000,000 an acre, RV sites aren't going to be as cheap. Get land values high enough, they won't exist at any price.
At vacation destinations, you are going to be paying destination prices, whether or not the destination interests you. If you want to be close to major urban areas, you will be paying prices base on land values and rent alternatives. You are paying rent on a chunk of land, it doesn't matter much what occupies that chunk, whether or not it fully fills the space.
At some state parks out here, if you want no hookups, you might park in the parking space for a tent site, but not put up a tent. The difference is not that much, e.g. maybe $12 for a tent, $16 for a RV site. But that's if there are actually tent sites, because many parks don't have designated sites for tents, rather a larger common tent camping area with no defined spaces.
Most RV parks I've been at, the base rate is premised for two adults, families might pay extra. No discount for us widowers and widows.
