If it has a front storage box, it's a good idea to check for tiny cracks. They are hard to see unless you really look for them and the leaking into the compartment can rot the floor. That's what happened in our 2002 Viking 2465st. We replaced the compartment floor and sealed all the leaks and never had anymore problems.
As for the price, we bought ours in 2008 when it was 6 years old. We paid $3500 for it. Used it for 6 years and ended up selling it 2 years ago for $4000 on Craigslist. The best way to figure out prices is to check what the going rate is for similar campers in your area.
2011 MicroLite 23LB
2012 Ram 1500 Crew Cab