1996 Pontiac Grand Prix?

Hi everyone. I bought my car last year and its in VERY good shape. No visible wear on the seats. Very clean kept. Never smoked in. Runs perfect. Before me it was owned by a mechanic for 10+years. All original. Fully loaded except for leather and sun roof. Regular maintenance. Has a VERY small stone chip on the windshield, and a bit of rust on the drivers side corner of the hood, and under the gas tank door. But its very minimal, and its just surface rust. I am hoping to sell it at the end of summer. I am having a new deck and sound system (amp/subs/deck) put in this week. Black exterior/grey interior. Never been in an accident. I am wondering what would be a good asking price. It does have high kms 350000+. Starts in any weather. What is a good starting asking price? It is a 4dr.