The starting "going price" used car dealers post is very often inflated. As the car sits on the lot they start lowering the price. Many times new members share what they paid for their cars. You can use the search function for new members and price to find some of those forum posts.

To best help you with a price other questions need to be asked:

Has the car been in any accidents?
How many owners?
Is it an automatic or manual?
Is there a documented service history?
Has it lived outside or been mostly garaged?
What color is it? Of course red roadsters are the best