Condition is a big factor but so is location. I'd imagine that it's worth more in NYC than the midwest. You might get more realistic price figures from Craigslist rather than car seller sites and magazines for something this old as they're often sellers with unrealistically high prices on something this common.
Remember that if you aren't in a rush, you can always ask more now and drop the price later. It might get more interest right before winter/snow.