TL;DR
All major US carriers have had those scrappy prepaid phones since ages, for folks who didn't really have the wherewithal to endure two-year contracts, or the credit history to get a subsidized expensive phone with set monthly outlays. The death of two-year contracts forced them to rethink the prepaid conundrum, too, and these are now very enticingly priced, plus the phones offered on prepaid are no longer scraping the bottom ...