I've spent many hours comparing the prices of different RV configurations. For the same size, age, amenities, and quality I would say the comparison goes about as shown below (comparing to a Class A plus a toad costing $100K). These are ballpark numbers, but reasonable. If you already have a car to tow in economic terms that doesn't mean it's free. Your tow vehicle can replace the car, with adjustment for cost of operation.
Class A plus a toad - $100K
Class C plus a toad - $90K
5th wheel and truck - $70K
Bumper pull and truck - $60K