I have a 1979 Mallard, 18 footer. Yeah go ahead and laugh, I paid under $2K for it, everything works just fine, and like others have mentioned, when I camp, I like to spend my time outside. Otherwise I 'd just stay home.
When we camp, we don't do campgrounds. Being near the Rockies and the Snowy Range in Wyoming, there are a lot of great campsites that aren't actual campgrounds. Typically I have to use 4 low to get to our spots.
I also pull a 5x8 trailer behind my Mallard with the dirt bikes on it, so we go places where we can do that, along with Fly fishing (upi would be amazed at some of the great fly fishing spots you can get to on a dirtbike / 4wheeler), etc.
My advice would definitley be to buy a used one, see if you like it, and if so, move up to something bigger. Also decide what kind of camping you are going to be doing. If you are going to always in parks with hook-ups, it will definitley change your requirements.
Personally, I like the old stuff, while it might be heavier (mine has actual 2x4's in the walls) my Tahoe still pulls it fine with the right hitch, and I own it. Not my idea of a good time to make payments on something I use maybe 6 or 7 times a year.
Here are a couple of pictures, the interiro is a trip (brown plaid and daisy pattern linoleum floor).
Bill