The phone must support it, and it must be activated for it. If you can't do it with that phone, there are new/refurbed prepaid phones out there for $30-$50 with some minutes to be had.
98.5 SVT
91 Escort GT (almost sold)
96 ATX Zetec (i brake to watch you swerve)
FS: SVT rear sway bar
WTB: Very cheap beater
CEG Dragon Run - October 13-15