yes, you can add the blackberry to prepaid as long as not on nonpay or lost/list. monthly talk plus data $30 required, but prepaid still has the unlimited data .
Are you talking about the Daily prepaid or the Monthly? You can not use a Blackberry on the Daily plan but you can on the monthly plan. You would pay about the same per month as Contract Plan.
Minnie is right - the Bold can only be used on a monthly plan, and requires the data plan. Prepaid is also slightly more expensive than the contract plans. You would be better off, if you own a BB already, to get a post paid account on a month to month basis.