We have recently completed our first year of caravanning, being a family that are tied to school holidays and like a mix of full fat sites to CL's.
A round up of site costs over that year:
Lowest cost night = £14 on a CL with 10 Amp electric.
Lowest cost night with electric = £15 on a CC Rally.
Lowest cost night fully serviced pitch with leisure facilities = £18 on a commercial site.
Fully serviced pitch night in school summer holidays = £30 on a commercial site with leisure facilities.
Grass pitch with electric night in school summer holidays = £33 on CC site.
Fully serviced CC pitch night in school summer holidays = £40
Serviced pitch night in school holidays = £23 on a commercial site near Alton Towers.
Fully serviced pitch night with leisure facilities at Christmas = £23 on a commercial site.
CC Membership per night away = £2.71
The highest price we have seen for a grass pitch with hook up is £68 +£10 per night booking fee in Cornwall the last week of the school summer holidays. We actually pitched 400 yards away for £23 with hook up.
As illustrated above, the CC sites are the highest price, with less facilities. In our experience standards are comparable across the sites we have used, not had a bad site anywhere yet. The other thing we find is the lack of open CC sites over the winter. We enjoy winter weekends away, leaving home after school on a Friday afternoon and there are no CC sites within 70 miles, but there are commercial sites with serviced hard standing pitches within 30 miles.
Enjoy your adventures.