Make sure it's an 09 model. Then, make sure it's being sold as new. If the dealership is closed, then it converts into a "used" model and that lifetime powertrain warranty isn't valid anymore. I can't remember the shut down date but it's coming up fast.
1/2 off would make me consider it. My mom bought a Dodge Caravan for $12,500 or so. I think MSRP was $19,000. No way it was worth $19,000, but about $7,000 off wasn't too bad. However, I'd rate the Patriot a little lower than the base Caravan. And this was years ago when the economy was still ok. You should typically get about $6,000 off MSRP off a Chrysler product in normal situations so for a dealer closing, I'd expect a ton more.