The deal goes live from 1 May and involves a BlackBerry Pearl 8110 smartphone handset and a year's worth of free internet, email and data. Calls and text-messaging are extra, so users will need to top up what is effectively a pay-as-you-go handset.
The T-Mobile BlackBerry Pearl handset was chosen because it is the most phone-like of the BlackBerry smartphones.
The idea behind the Pay Once offer is to tempt customers who like the idea of web connectivity and the advanced feature set of a smartphone but have until now been put off by the complex data and internet access charging bolt-on costs associated with them.
T-Mobile research showed that there's a significant group of customers that wants a smartphone but didn't see a BlackBerry as an easy-to-access device. By simplifying the cost structure, T-Mobile hopes to win some of those customers.
T-Mobile also believes the Pay Once concept will appeal to small businesses that need to stay in touch but aren't able to justify a hefty monthly fee or expensive data charges.
Once their year of free internet and email use is up, BlackBerry Pay Once handset owners will be able to sign up again for a further year's usage on the same deal, albeit without getting a new handset.
The BlackBerry Pearl 8110 comes with a 2Mp camera with zoom, a video camera, voice recorder and built-in GPS. The handset will be offered in silver only and will be preloaded with popular applications such as Facebook, MySpace, AOL Instant Messenger and Google Talk.
The handset has its own built-in music manager that synchronises with Windows Media Player and Apple iTunes libraries, the latter on both PCs and Macs. A 1GB microSD memory card is included, as is a pair of stereo earphones.
RIM's spokesman explained at the Pay Once launch event that of the 25 million BlackBerry users worldwide, 50 percent are non-enterprise users who use webmail rather than their corporate email service on their handset.