Question about Blackberry Bold purchase

Currently I own a Blackjack II with the contract ending in July 2009 (ATT)

The question is Am I able to go on let's say Amazon.com and purchase the Blackberry Bold for $249?

I don't mind getting a 2 year extension just to get the Blackberry Bold at that price but is it possible to do that?

I don't mind them adding the 2 years on top of my existing contract as i been using ATT for the past 5 years.

I just don't want to shell out $600 (including New York Tax) for a Blackberry Bold.