The first reason Mint is cheaper than T-Mobile is the fact it’s an online-only service, thereby with lower running costs. It offers the plans in 3-month, 6-month, and 12-month bulk instead of one month. Then your service has access to fewer perks, in which case you miss features like domestic roaming, priority data, and unlimited data with no cap. Mint also doesn’t have free entertainment subscriptions, such as Netflix, Apple TV, and Music on T-Mobile.