Value varies depending on where you live. Bikes like that flightliner, especially in the shape it appears to be in, don't show up around here very often (or ever ). If I saw that on my local CL with a $150 asking price, I'd be on it. I'd offer much less than $150...mostly because I'm not much of a flightliner fan, but I'd still be all over it .
Those were only made from 1961-63 with a chrome frame. It has the truss fork instead of the springer, so it's just below the top Flightliner. In '64, the new Spaceliner took over as top model, they were offered in chrome, the frame is a different style. -Adam
If the wheels good and straight, and it rides nice and solid, I'd offer $100 and barter from there. I always let them see the cash in my hand to speed up the process. There's nothing new for $150 that's anywhere near the quality and coolness of that bike. I agree with the 61-63 Sears, Here's a 63 Stratoflite, the chain guard says "Flightliner":