Time’s Eric Aamoth helpfully offers five things you should know about T-Mobile USA’s new plans, which the carrier will officially announce tomorrow morning. A $50-a-month plan includes unlimited voice and messaging and 500 megabytes of data, and family plans start at $80 for two phones and top out at $210 for five lines.

But things get a little more complicated when it comes to buying a new phone with service. T-Mobile will become the first of the top-tier U.S. carriers to drop phone subsidies and service contracts, opting instead to allow users to either pay the entire cost of a phone up front or make monthly payments until the handset is paid off. U.S. consumers have long been accustomed to picking up subsidized phones on the cheap, then being locked in to two-year deals that can ultimately be far more expensive. The challenge for T-Mobile, then, will be in explaining to consumers why it’s sometimes in their best interest to pay much more for the handset itself — if that purchase allows them to save money in the long run.