For my first PDA type phone, I just got the Centro from Sprint last week. Darn the keyboard is small, but I am getting used to it. It's just $99 with the 2 year plan and after $50 MIR. I also just signed up for the Sprint SERO plan. See more info
here. I got the 1250 min plan for $50 a month and that includes unlimited data, pic/text messaging, ect. They also have a 500 min plan for $30.
I am going to call Verizon today or tomorrow and attempt to get out of my contract without an ETF due to the recent fees that verizon has changed on the bill. Send me a PM for ways to save $25 on your first bill if you are new to sprint.