They can be had, but it could take time. One of the big advantages we have when we buy used is a historical track record of the chassis and coach manufacture.
ALSO - since you are new to this game - you probably have no idea if this fits your lifestyle, so entering in at the lower end of the market, you will not have a big investment if things don't pan out.
I recommend start looking now, I am very good at mechanical stuff, I fix everything myself, I have the tools, knowledge, and experience to work through almost any problems. If you have these same skill set, you will make a sweet deal that you will be happy with.
Avoid getting emotionally involved, do not buy the first thing that you look at, HOWEVER, be prepared to jump when a good deals shows up, BUT, it must fit your evaluation of facts, not emotion.
The last one is the hard one - Whats a good deal?
Learn what to look for, be ruthless in your negotiations. The seller wants to get the most out of it, you want to spend the least. After you've looked at 6-10 of these, you should have a good idea of what your dollar will buy.
There is a a vast difference in manufactures and systems - The Mirada we bought is a very basic MH with basic systems. You will see this in your search
You are looking in the same price range that I operate in. I was able to locate a very nice unit (needed some minor work and upgrades). The seller wanted 21k. I drove it home after giving him 13k in cash. I wrote a short article on our Search:
http://www.2001mirada.com/the-search/
While you're on my Mirada web site, look around and you'll some of the problems and issues I ran into. You will see many of these same issues in your search. I knew about most of them from our pre-purchase and negotiations.
Older vehicles - very basic what needs to be looked at.
1) Water damage - mushy, water stains, delaminations, walls splitting and flaking.
2) Windows, roof vents, roof, sealed and no leaks.
3) Major components functional - frig, furnace, water heater (water systems) Air conditioner, generator
4) Vehicle functional - Research the chassis types, learn what their historical problems are. Periodic and preventative maintenance currency.
5) Tires - major cost item.
6) Time of Year - fall / winter is best time to buy, prices are lowest, spring is worst.
6) Location - Southern states seem to have greater inventory, lower miliage, and lower prices.
Start looking, learn as you go, If you are a smart buyer, you know what to look at, you know what the costs associated with what your looking at, you will find a great deal and know exactly what you got into.
If you get emotional and jump on the first thing that goes by, you will be deeply in debt with a money pit that is constantly breaking down.