Like Sabre Dance wrote, they may be looking to restock the used car lot. I had a Saturn Vue Red Line that I traded in and they gave me good money for it. Although they started at $3,500 and eventually gave me $9,500.
You really just need to say no a lot and walk out after about 20 minutes. Take their card, leave them your number, say you'll call tomorrow and don't. They'll call you back.