Go to a Sams (Superstore for bulk items owned by Wal-mart). Most have a sprint booth in them where you can get a Black Berry as low as $50 for the Storm 2.
I have the blackberry curve 8330M, and I got it for $35. It had to be included in a 2 year contract, but in can be a family plan. So now, me and 4 of my relatives all of Black Berrys for $35 each with unlimited texting, internet(data), mobile to mobile calling, and 3,000 shared mobile to land line minutes for about $250 a month.