Last week, AT&T reduced its unlimited data prepaid plans by $20, bringing its two options down to $45 and $65. And earlier this week, Verizon followed suit by dropping its prepaid unlimited data plan to $65 for a limited time.

While T-Mobile's discount puts its plan at a competitive price, there are some caveats to keep in mind. The plan is approved for domestic use only, unlike AT&T's plan, which allows for talk, text and data use in Mexico and Canada. Both AT&T's and Verizon's plans also offer unlimited talk and text to Mexico and Canada. T-Mobile's regularly priced Essentials Prepaid plan, on the other hand, offers unlimited talk, text and data at 2G speeds in Mexico and Canada.

Additionally, T-Mobile says video will typically stream at 480p with its $50 per month plan, and customers using more than 50GB of data per month may experience reduced speeds during times of congestion. Tethering is also at a max of 3G speeds.

T-Mobile didn't say how long its deal will last. You can find out more here.