It's easy to shop by phone/internet now-a-days.
You can get the invoice prices off of Edmunds.com, then use Chrysler.com to find the vehicle you want in your surrounding area....then you can call those dealers with the car you want and ask if they'll sell at invoice + 100/200/etc.
All the links I mentioned are in the Links at:
http://www.ptcruiserlinks.com/links/....asp#newbuyers