What kind of camper or RV do you have?
Bob, This is a long answer. I am not sure I should post in this thread, but here goes... This dates back to when I was a kid.
We have done a few things. We started out with 4 people (family) then last year just my brother and I traveled. So our first RV was a 1982 34' Airstream that my dad bought when I was very young (I think 3) We lived in Mexico in the winters in that until we bought a sailboat. The Airstream made 16 trips, with 2 times to Guatemala. In 2004 my brother and I were getting older, so we bought a truck camper (1993 Hallmark 8.5') and my parents went from sleeping on the front couch (makes into a double bed) to a queen over the cab of the truck. In 2008 we sold the 1982 and bought a 1983, exact same model (34' triple axle) that had spent its life in an RV park (it still had the original tires on it) for 12k. The '82 had over 250k miles and although it had held up very well, it was getting tired.
Last year we were only 2 people so we left the Airstream in back of my house and just drive the truck and camper.
For trucks we have used 2. In 1996 we rebuilt a wrecked 1991 Dodge Cummins. We made it into a club cab and as kids we would ride on a little seat in the back. Then in 2005 we bought another 1991, this time it had been extended into a full 4 door crew cab. It had issues and the day after we bought it the transmission froze in 5th gear. So we parked it and bought a van. Which we drove behind. The next year we rebuilt the transmission, replaced the entire cab, and repaired the broken frame. I have since rebuilt the transmission a second time. Plus numerous other repairs. But never touched the motor. It still runs great, at 458k miles. If you can believe it, I get 20+ mpg with the camper. And 15+ with the whole rig (one 300 mile trip we got 16.9) To be fair it is a slow operation, I just drove from Houston to Pensacola, and then to West Palm Beach, FL. I passed a total of ONE vehicle. The truck likes 57-60 mph.
I found a photo of the rig, and then just the camper. I will attach it, for anyone that is interested. The rig is parked in the photo along side the Walmart in Cedar Rapids, IA in 2008.
As far as spending goes... We drive a LOT. In the last 4 days I have driven 1500 miles. If you take out fuel, or at least excess fuel, the lifestyle is very inexpensive. Food... about 10 gallons of propane a month, more if you want hot water all the time... We get water from Flying J or sometimes Walmart has a faucet. sanidumps lists all the RV dump stations and generally we can find one for free. We have a 327 watt solar panel with 2 batteries, I never run the generator unless I need A/C.
I am working on figuring out exactly what I spend a month. Probably ~500 on fuel, some months more... and 1,000 on non fuel items. You could cut down on this a lot if you weren't driving 3k miles a month.
I do find that because I am always at Walmart/Sams, I never buy very much, and if I am away for a few days, it is a major pain to go to the store, since I normally just walk in.
-Brian (writing from Fort Myers, FL... parked at Walmart)