Your best bet is either eBay, or comparable 'cell phone enthusiast' forums. I have a shitty Nokia 6010 I adore from TMobile because it does almost nothing but work as a phone. I used an unlocker and now I can run it on any network that does 950/1800 (that supports these frequencies).
Make damn sure the one you buy will support the frequencies your carrier uses, or you're double-fucked.
