Despite T-Mobile USA being very comfortable with prepaid service, it hasn't jumped in with both feet like its potential partner MetroPCS or its arch-rival Sprint. The company has just confirmed to FierceWireless that it's not waiting for a merger to experiment further; it's currently trialing GoSmart Mobile, a prepaid-only network that uses data speed, not caps, as the incentive to jump to higher tiers. Paying $30 per month offers unlimited calling and texting with no internet access whatsoever, while $35 a month includes unlimited 2G data and $45 upgrades to 3G. While that's not as good a deal for data as Virgin Mobile, it's better for those who truly prefer unlimited voice. The carrier hasn't said how it would balance the new service with its MetroPCS, but it has some time to sort this out when any possible nationwide launch won't take place until 2013.