25 Feb 2016 There are tons of trade-in programs that will buy your old phone from you in- store at big-box retailers, you'll find the majority of them online. AT&T, T-Mobile, Verizon and Sprint all have plans that enable customers to upgrade their phones On Demand plan ends up being the cheapest net cost for an 1 Aug 2019 If you haven't looked for a new cell-phone plan in a while, you may be with one of the Big Four carriers (AT&T, Sprint, T-Mobile, and Verizon Wireless). of apps, content, and gaming options from iTunes and the App Store. 20 Feb 2020 Some of these phones are very cheap, and Amazon is making a small selection Some unlocked phones may not work on Verizon or Sprint.