The prices of used motorhomes are available at NADAGuides.com in the RV category. From the RV page click on Motorhomes, select the motorhome's manufacturer, model type, year, mileage and click continue. The final page lists the motorhome's average retail and low retail prices, based on used condition.
Prices for used motorhomes are also available at RVTrader.com, as of 2015. Select the motorhome's class, make and model and press search. On the search results page select Condition and check Used. The average used price for the motorhome is displayed at the bottom left of the screen, based on RVTrader.com listings. The price checker also displays the lowest and highest priced models currently available.