Just search, "Mobile Home Buyers" and you can look for companies that give free quotes.
I found this which looks free, "http://www.mobilehomesell.com/form/
Send the address (doesn't have to the space number) and someone may be able to assist you. One of the best ways is to talk to the manager of the trailer complex. They have a really good idea of what is going on in terms of recent sales, relocation, and your local values.