Can I use my upgrade on A Blackberry w/o changing my plan(not activate it)??

[gullzway]

I am out of contract and eligible for an upgrade discount with Sprint. However, the Touch Pro2 from Sprint is a rediculous $350 With renewal, when U.S. Cellular's is $99 and Att & Verizon's are $199. My friend has a Pro2 but needs a Blackberry for his new job. He's not eligible for an upgrade discount and said he would trade it to me. Could I use my upgrade on a $49 Blackberry 8330 and not Activate it, then trade it to him for the Pro2. Will they make me change to a Blackberry plan for getting the phone or only if I activate it?? I do not want to change my plan whatsoever,( $39.99/450 min with $15 unlimited data @ 22% employee discount= $43/month.)Thanks for any insight!