T-Mobile has said its high-speed data network at 4G speeds with HSPA+ can reach 21Mbps on an uncrowded network, while its 2G network, also called EDGE, can drop down to below 100 Kbps.

Tiered pricing plans such as T-Mobile's are gaining steam, with AT&T the first to do so last year, charging more than T-Mobile at $15 a month for 200MB of data and $25 a month for 2GB.

Verizon Wireless said it plans to introduce data pricing tiers this summer on and is considering , similar to how voice minutes are pooled.

As part of T-Mobile's announcement, the company noted that an unlimited family plan for two lines will cost $139.99 per month, which includes voice and text and 2GB of high-speed data. Two weeks ago, the carrier had announced a similar individual plan for one line costing .

In addition to the four new pricing plans, which require a two-year contract, T-Mobile also announced two new pre-paid monthly payment plans that incorporate speed limits on 4G service. They are $50 for unlimited talk and text and 100 MB of data at 4G speeds, and $70 for unlimited talk and text and unlimited data with the first 5GB of usage at 4G speeds.