Hey man, lots of info about local play over at http://www.grdgc.org
We don't have many options for plastic at brick and mortar stores. Sonny's Deli by Ellison and English Market by Basil both have a rack of assorted discs.
Your best bet locally is to contact someone that sells out of their trunk.
Tony Inzana, TD of the AM Worlds, has a good variety of Discraft, Innova and Gateway... firstname.lastname@example.org