Using an RV (Recreational Vehicle or motor home) on a trip is as close to camping as some people ever get, and other people would probably argue that it's not even really camping.
Camping is traditionally a cheap way to go on vacation, but using an RV can often be more expensive than staying in hotels. There are a few major costs that it is important not to overlook with an RV:
The RV itself: RVs are expensive. They are expensive to buy and expensive to rent. They are even more expensive to rent because, of the rentals I've seen, they rarely include unlimited miles so if your trip is very long you can start racking up mileage charges at a shocking rate.
Gas: RVs are gas guzzlers. Most get around 5-6 miles per gallon, with some getting up to 10-11 MPG. To really figure out the cost difference between driving your car and driving an RV you should figure out how much it would cost to drive to your destination in a car and compare that to how much it would cost in an RV. At $3/gallon, for a 100 mile trip if your RV got 5 MPG and your car got 20 MPG, the RV would use an extra $90 worth of gas.
RV parks/campgrounds: Another expense to consider if that people usually bring RVs to campgrounds or RV parks, and those have nightly fees. Those fees aren't usually as much as a motel, but they still add up, especially on top of the other costs.
As expensive as RVs are, they are also a lot of fun and there is a reason there are a lot of them on the road. A road trip in an RV is great for a family where the kids don't have to be strapped into car seats, passengers can sit at a table and play cards, and there is usually a restroom on board. A trip in an RV is a great experience, just be aware of the costs going into it so that sticker shock doesn't ruin your trip.