My current setup (truck and fifth wheel) cost me $8000 in 2003. I bought them from an elderly woman who was a friend of a friend. They had bought both new, and taken very good care of them. Fiver is a 1993 Coachmen, truck is a 1989 Ford F250 XLT Lariat 460 EFI. The truck had been garaged since new, and even at 14 years old, only had 36K miles on it. It had only been used to tow the trailer..even still smelled new. They used it until he died at 90, and she was 89 years old and couldn't use it, so she had to let it go.
I've since put about 8K more miles on the combo, and it has been very reliable with only minor maintenance and a repair or two. I changed a leaking master cylinder last summer, and both power window motors about 3 years ago. Other than that, change the oil and drive it. I did have to replace the tires on both, as they were dry rotting....keep this in mind when buying an older rig.
The deals are out there....especially with the economy in the state it's in and Christmas coming up. A lot of folks are out of work and need the cash, and are willing to let their toys go cheap. And even though gas prices have fallen, it's only temporary, and people know this. Ask around people you know who RV...watch Craigslist, eBay, local classifieds, etc.
Good luck on your search.