Much less than $15K!
Silverlining had just 1,700 hours total time airframe and engine when I sold her in March, interior a strong 8 (completely redone interior in 2004), exterior a decent 6, four channel electronic EGT/CHT, Metco Wingtips, Whelen Comet flash strobes, MX300, Child seat, Hooker Harnesses, Spin On Oil filter kit, and even a VG kit (uninstalled) Price: $16K.
If that price seems kind of low, here is my math: The engine was 40 years old and near TBO, never been overhauled. Cost to overhaul the engine, somewhere between $8K-$10K. As I see it, the airplane would have been worth about $26K tops with a fresh engine, about $24K with a midtime SMOH. Do the math, $16K is fair.
Hey, I know lots of folks ask far more for their airplanes, believe me, they cross my desk everyday. In my opinion, the typical asking price is about $5K too high. I also see airplanes advertised month after month without selling. I set my price fair, sold to a friend, we both knew the price was correct, so no haggling required.
The airplane you're describing? I personally would not pay more than $12K for it, if I'd buy it at all.