While I respect Aus78Formula opinion, I disagree on a few things. Good condition is always worth more than mediocre or terrible. Not everyone who would buy it is looking to put $20-25K into it. I think you will find buyers that will want to a good daily driver they can bring to life with just a little work. That's what I have done with mine. After 3 years it is almost done....its been an absolute joy to work on.
That being said....while rot on quarters and doors is better than rot on floors or around window seals - it is rot none the same. There may be other bad things as well: suspension bushings, dirty gas tank, dry engine and transmission seals that may start leaking once driven, etc.
It is hard to estimate a price without pictures but I would say, if it is what you say it is, the 5K is probably a little low - especially if it is a 4 speed manual transmission with t-tops and factory a/c. Some articles I have read say to estimate, over the base price, an additional 10% for each.
One technique you can used to judge the market and the value of the vehicle is do a craigslist search for Trans Am's in your area and others. Make comparisons. What are others asking for ones in similar shape -better shape -worse shape? But remember....just because they are asking for it doesn't mean it will sell for that amount.