Look at either the unlocked/unbranded Nokia E72, C6 or E5-00. All offer GPS in combination with the free Nokia Ovia Maps Navigation software you can download for free if it's not already included on the handset. They load the maps/data locally and also give you turn by turn directions. All you need is a clear sky while running the Ovia maps app- no data plan is required, so you could go either pre-paid or post-paid since ATT or T-Mobile doesn't sell that particular model.
Example product search using froogle-
I'm looking to get a smartphone with GPS capabilities but I'm cheap and I don't want to pay for a data plan. I know that the phone with have to have a stand-alone gps and not a-gps but past that i'm a bit lost. What cell phones have stand along gps and how would I get the gps to work?