Hi & welcome. Trailers, unfortunately, aren't like cars where there are certain models and years to stay away from because of known problems. Trailers are pretty much assembled by hand using parts from most of the same suppliers. So the quality seems to vary a lot from one trailer to the next of the same model and year. I would say FunFinders in general are on par with most of the manufacturers out there, and I personally have had very few problems with mine. I have a 2009 210 WBS and we love the layout, it fits our needs perfectly.
Since your buying a used trailer a lot will depend on how well it's been maintained so you should do a thorough inspection before buying. Especially check for signs of leaks. Any trailer that hasn't been properly maintained is subject to leaks that can cause a lot of damage. A quick internet search should turn up a plenty of checklists you can use.
As for price, I can't help much there, but you might search the net and see what others are going for. Good luck! Hope it turns out to be a good deal.
2011 Chevy Silverado Crew Cab 4X4
2009 210 WBS