I get 3 GB of data till it's throttled. However...
T-mobile doesn't have any towers near my university and therefore I get 50 MB of data a month because it's domestic roaming then.
It's pretty hard to budget 50MB of data a month. There's wifi most places on campus, but in maybe 20% of those places it doesn't work because they're too many people on one network. And of course those are the important places like the cafeterias.