Shearwater,
Start with used.
New are 9~14K$us....
Used on Craig's list are 1~5K$us depending on lots of things.
These are unloaded for two good reasons:
*- The kids have grown and they don't use it anymore.
*- They upgraded to a solid RV and need to get rid of this.
Both are in your favor.
Keep opening up the search circle and learning. It is a given that the warranty in today's RV market is useless, so don't pay a new price.
You will want new tires no matter what you get, but pay attention to the load ratings of both your tow vehicle and the unit.
Good Hunting
Matt