Probably the most offensive aspect of smartphone use can be the data. T-Mobile's cheapest data plan costs $10 four 200MB and use above that amount used to be throttled.
T-Mobile plans to end the throttling method on the $10 plan and start charging an overage charge of $0.10 per megabyte will be assessed upon exceeding the 200MB limit with a maximum overage charge of $30. Customers will receive a text message when they reach 200MB alerting them of the overage charges and given an opportunity to change to a different data feature.
T-Mobile notes that the 200MB feature has exceeded T-Mobile's
expectations so "in order to remain competitive" and continue to offer
the rate plan it will be grandfathered on of August 13th. After that new data pans will be charged overages.
The throttled data was probably good enough to receive the e-mails but not surf the web quickly, making the cheapest choice for data out of any carrier, but not after August 14. the AT&T 200MB data offering costs $15 and $15 per 200 MB over that amount.