Use nadaguides.com and kbb.com to determine what range the bike is probably worth. Then adjust (if you can) for local conditions. For instance, CA residents seem to pay much more than the rest of us for bikes. Remember those listings presume the bike is in excellent shape, which you've described is not the case, so discount probably applies.
And a used bike is an excellent first choice.
Dragging knee is for the track, and dragging tail is for the lot. --Kane Friesen
When you're in a car, you're watching a movie; when you're on a bike, you're in the movie. --Robert Pirsig
Identity theft is not Fun