I agree. $3000 is in the low-to-middle range price-wise. Better than a project, but not fully camp-ready.
I also agree that the biggest single issue I'd check for is floor rot. I wouldn't just look under the trailer, since most rot starts from the top and results from
leaks at
windows, vents, and plumbing. Take a flashlight and screwdriver and test the floor inside. Pay special attention inside seats and cabinets near the perimeter of the trailer. If there is any significant floor rot, I'd pass.
Regarding the
axle, in addition to doing the "fist test," I'd also check for uneven tire wear and jack up each side of the trailer (a small floor jack on the frame near the
axle, never on the axle itself, is best). Make sure the wheels drop down as the frame goes up. Little or no movement means the rubber inside is hardened and the axle is shot. If so, I wouldn't necessarily pass on the trailer, but I'd try to negotiate down the price a bit. A new axle will run $600-800, but it will be a good investment, and you can add
brakes, something most older 13'ers don't have and many modern tow vehicles require.
In general, at that price and age, you need to have a "rehab fund" in your budget. There will be issues. Wiring can be problematic. You may need new
tires (over 6 years is worn out, regardless of tread) and you'll want to service the bearings. A lot depends on how handy you are.
A link to the aforementioned buyer's checklist is here:
Fiberglass RV - Document Center