Gary forgot to mention wives.
By far, they are the most expensive.
I made the same plunge, thank goodness a longtime friend was selling his rig as I was approaching the breaking point, dealing with dealer offerings.
My RV buddy who used to maintain motorhomes for a living put it best: "The ones that are used regularly are the best; and, never forget that rubber dies."
What he means is that a '97 driven 10,000 miles might be more of a challenge than one with 80,000 miles if the hoses, belts, and tires have been left alone on the former due to mileage. Ten year old rubber is like your grandma's knees: failure is imminent if pressure is put on 'em.
Good food for thought. The only other thing I can pass along: recently, dealers have been snapping up rigs at 60 cents on the wholesale dollar. As a buyer, you rule the market, no matter what they say. Take your time, and don't buy anything for more than wholesale NADA.