Cool video by @ZacksJerryRig about how the back glass of modern apple phones can be removed.
Broadly speaking, if you have a "USB" cable that only connects pins 1 & 4 then you will get power and no data (Best Buy was selling cables like that as Universal USB Charging Cables a while back, not sure if they still do). Likewise, if you have a cable with only 2 & 3, you will get data but no power. If you're curious, here's a Wikipedia page with the standard USB Pinout.
Mint Mobile, a new service. I think they use ATT network but need to confirm. NOPE they use T-mobile