Simple Choice Data Stash Plans w/ Rollover Data" page with details of how Data Stash works and which plans it works with. The information about Data Stash for prepaid is hidden within the click to expand Questions about Data Stash section at the bottom of the page. Key points for prepaid customers are:
- Prepaid plans eligible for Data Stash are the $60 and $70 Simple Choice Prepaid plans.
- Prepaid Mobile Internet plans are not eligible for Data Stash.
- T-Mobile will give every prepaid voice customer with a qualifying Simple Choice plan a one-time bonus of 10 GB of data.
- New customers who choose the $60 or $70 Simple Choice Prepaid plans will get their 10GB Data Stash bonus at time of activation.
- Existing customers with eligible plans will receive their 10GB of Data Stash bonus data with their next renewal after March 22.
- Unused data from the 10GB Data Stash bonus expires on 12/31/15.
- Beginning after the 10 GB bonus is used up, unused plan data will roll forward for up to 12 months.
- Rolled-over data expires 12 months from when it was added to the Data Stash.
In spite of their premium status, T-Mobile makes the Simple Choice Prepaid plans hard to find. They aren't listed on T-Mobile's main T-Mobile Prepaid Plans. Prospective customers are funneled to the inferior throttled Simply Prepaid plans. The only places I've found on the T-Mobile site that list the features and pricing of the Simple Choice Prepaid plans are when activating a new T-Mobile prepaid line of service, or for current customers, when changing plans on the My T-Mobile online account management site (image below, click to view full larger).
Related: Prepaid Operator Profile: T-Mobile