The plan does not include data and the Unlimited International Talk and Text add-on is not available with this plan.
I don't have a lot of details about this offer but presumably customers who activate during the promotion will be able to keep the plan indefinitely. I also don't know if this plan will only be available though T-Mobile authorized dealers or if it will also be offered online or at T-Mobile corporate stores.
This plan has fairly limited appeal, in my opinion. It's a good deal only if you don't need data but do need access to roaming off the T-Mobile network. If you don't need roaming there are less expensive T-Mobile based unlimited talk and text only plans including $25 plans from Spot Mobile and Simple Mobile, both of which include unlimited international texting. There's also Ultra Mobile's $29 plan which includes unlimited talk and text, including international texts, plus 100 MB of data and 1000 minutes of international calls to 70 countries. See T-Mobile and T-Mobile MVNO Prepaid Plans Compared for other options.
Related: Prepaid Operator Profile: T-Mobile