buy an iphone and open a line with tmobile. unlock the iphone and BAM! cheaper service.
you can also look into the SERO deal from sprint. i get free sprint to sprint, unlimited text, unlimited web/data, 1500 anytime, unlimited NW with nights starting at 6, and incoming minute free, plus the insurance for a whopping $66 a month with taxes.
i have a treo with 2-4GB (8GB total) SD cards for movies, music, and my word documents so i can edit homework on the fly. i also use it when taking tests...works pretty good