Well, If you have a 100% disability you get 1/2 off in some State parks, Fl. is one I know of.....
COE(Corp of Engineer) campgrounds are nice to stay at, cheaper than 45 a night.....
also some cities have campgrounds(I have been to a few but wasn't pleased with upkeep).
Gas shouldn't be too bad if you are only going to move 2-3 times a month, as long as not big distances between.
Some places give a better rate for the week or the month.....
or you can hit some of the ones that advertise in the RV magazines for 3 night stays to get you in and scope out what they offer( don't have to obligate though).....