National Automobile Dealers Association guides are available for recreational vehicles with enclosed trailers but not storage or hauling trailers. There is no official guide for noncommercial enclosed trailers designed for storage or hauling.
NADAguides provides detailed value information for travel trailers, fifth wheels, motor homes, camping trailers and truck campers.
There are guides that list the prices for enclosed commercial trailers; however, these guides are generally intended for commercial use only and tend to cost several hundred dollars. Typically, unless a business is buying and selling trailers, a telephone survey or Internet search should give a reliable idea of the value of any trailer an individual is looking to buy or sell.