I would say somewhere in the $1500-3000 region. That's about what I've been seeing for a good used car. Charging the A/C is fairly trivial to do, and may net you an extra couple hundred bucks, so I would try that. Personally, I would not pay more than about $2500 for any car in non-running condition. The timing belt is a bit tricky if you haven't done it before, and is extremely cramped if you have the 3.0. The real deciding factors for me would be rust, condition of paint and interior, and the extent of the damage on the fender. The more you get done, the more you'll get for it. If the car's a real gem, I would do the timing belt and the A/C over a weekend or two. That could easily net you a grand and will almost certainly attract more buyers.