The Blue Book says the F series were produced from the late '70s to early '80s, flattop dreadnought. F3 to F115 were retail priced $149 to $895. Used market prices depend on condition and demand, $50 to $150. My guess is that anything over half that is questionable, even for mint condition. Fender is not known for its fine acoustics, and in todays market where there is a glut of decent entry level guitars (search, we talk about them all the time here), there are better choices.