My god those 250 prices are nearly as crazy as house prices. A lot of those CBR250's, ZX250's and FZR250's are twenty years old - older than the people buying them! Honda, Kawasaki etc stopped producing those things over ten years ago and those 250's which are being imported now would have sat in warehouses for years and years. It's good that they're fundamentally well built - they cost nearly as much as the larger (600/750/900cc) bikes to manufacture and costs were saved in the suspension and brakes. But if they've sat around for years and years seals can dry out and perish over time, oil can sludge up, incorrect radiator coolant can corrode the water galleries so it can be a bit of a risk buying those old 250's. As they would have been traded in, were worth next to nothing (japanese roadworthy laws and the three year old rule) and more a thing to be recycled into beer cans and park benches rather than resold and ridden again not much care would have been taken to prepare them for storage.

If I suddenly found myself 18 years old again I'd get a one year old Ninja 250. They're cheapish to buy, more modern looking, you can get some bits to jazz them up a bit and they can corner fairly well. Save the big bucks for the next bike!