The main difficulty with mobile homes is that they are considered a motor vehicle, not a "house". Therefore, you cannot obtain a mortgage. You need to find alternative financing, just as you would for the car you drive. This makes MH more challenging to purchase and therefore resell.
Check a little bit more into financing the MH and also the $20. A month fee, that sounds very cheap. Most of the MH parks charge a few hundred, that's how the owners who own the land make money.