The FG-251B is considered to be a good quality guitar, and it is often sought after by collectors and players alike. The value of a vintage Yamaha FG-251B guitar can vary depending on a number of factors, including its condition, age, and provenance.
In general, a vintage Yamaha FG-251B guitar in good condition can sell for anywhere from $500 to $1,000. However, guitars in excellent condition or with rare features may sell for significantly more.
If you are interested in selling a vintage Yamaha FG-251B guitar, it is important to do your research and determine the guitar's fair market value. You can do this by looking at recent sale prices for similar guitars on online auction sites and classifieds websites. You can also consult with a guitar expert or appraiser to get an estimate of the guitar's value.