1978 280z

With no pictures and the description you gave.....maybe 200 bucks. That is to say that a lot more info is needed.

You didn't tell us the mileage, the condition of the interior or paint (on a scale of 1-10), the amount of rust the car has (where are you located? ), you've given us ZIPPO to work with.

I think we can safely assume EVERY piece of rubber on the car is rotten, including brake cylinder seals, tires, door seals, grommets, vaccum and fuel hoses, and that the tank is rusted on the interior...

My offer would be $150 until you provide at least a dozen, in focus pictures of the car.