Rates vary wildly by location - Florida and CA seems to have the highest and AZ/NM some of the cheapest. Monthly rates give the best "daily" rate, weekly is discounted and of course daily will be the highest. AZ monthly rates for a nice park seem to average $5-600 per month plus electric in Yuma/Lake Havasu hich can add up.
Thousand Trails works well for some fulltimers BUT the parks are not close to major cities generally, annual rates keep rising and they keep adding more cabins/park models reducing the usable RV spaces. We have been members for a long time and dislike the direction and lack of upkeep at some parks. (Maybe try a TTrails Zone Pass for a year and see how you like the parks.) Also - you can stay for a max of three weeks in OFF season and two during high season at popular parks with your membership. When we make an effort, we do OK on use/cost for a year but we have to go where the parks are not necessarily the routes we wish to travel as a first choice. When we go and stay for a longer visit is quite nice!
You really need to decide where you want to go and stay and I'd recommend budgeting $6-800 per month including electric
and MORE if in a resort area. If it is less, great..................Happy Trails!!