The biggest cost you will have is when you you have your A or C on the road. Figure 5 MPG then add the cost of fuel (and oil) and it all starts to add up.
Periodically you have to change out fuel and oil filters and class A diesels take oil by the gallon (really a lot of litres). Figure oil changes every 10,000+ miles (depends on the diesel engine) fuel filters every 25K+/- miles.
I am not sure what class A tires cost, but even if you don't wear them out you have to replace them every 3 years or less.
If you are going with a class A or C you are goind to have think about a toad. That is the car you see being dragged behind the class A, C.
Maintenance is another expense. Class A is really a bus. I am guessing you can get away with a few years of minimal maintenance. At some point you are going to have to have some major maintenance. I have no idea what that costs.
The other maintenance is going to be the RV itself. Every year you want the roof checked, slidelouts inspected, anode rods changed every other year, awning inspected (awning will probably need to be replaced every 3-5 years)
You could shop used. Depreciation is huge on any RV (A,B,C,TT,TC,5ver, hybrid). An RV (toyhauler) we bought that was 3 months old had lost a third of its value. Be aware that used are sold as is and if you discover a major problem after you sign, gues what?
Also if you purchase at the end of the season you can save more money.
It is rare that a trailer can be worth more than you paid for it. They aren't like houses and they do wear out.
The other option is to look at travel trailer or 5ver. The advantage here are that TV (tow vehicle) and trailer are separate. If you have trouble with either you can leave it at the shop. With a class A or C the whole rig is in the shop.
If you have trouble with the TV, you can always replace it. That is a little tough to do with an A or C.
If you are still going to keep a home, you can always use the RV as a lifeboat. We have hurricanes around here. If the power gets knocked out we fire up the gensets and live in the RV until the power comes back on. If we are having a party or family get together, we have extra fridge space and ovens, burner space as well.
