You can make it what you want. I know people who have full timed for less than $1000 per month. They only stay in National Parks and are self contained. They dump when necessary, use the campground baths, use 12 volt appliances, run the generator only when necessary, have solar panels to keep the batteries topped off, etc.
If you buy a used 5th wheel, or TT, and a used truck to pull them it is not expensive. Many people live this way. Stay parked longer and save gas. There are many free campgrounds all over the country. In fact, go to www.freecampgrounds.com
to see a list.