In many ways, nothing beats the freedom of an unlocked phone. Unlocked phones work with any AT&T or T-Mobile SIM card, even with no data plan. You can pop in a local, pay-as-you-go card overseas and never pay horrendous international roaming charges, and you don't have to deal with carrier-installed bloatware.
Tired of your handset, or want to own a few and switch between them? With an unlocked device, you can trade up or sell your phone whenever you want, without waiting for the end of a leasing or equipment installment plan—because you're not in one. You can own multiple handsets and swap your SIM card between them. You can also take advantage of super-cheap prepaid plans from virtual operators piggybacking on the AT&T and T-Mobile networks.
At the same time, there are a few downsides to going the unlocked route. If you change SIM cards overseas, you won't have your US phone number while you're there. And unlocked handsets generally work only on GSM networks (AT&T and T-Mobile), although there are some exceptions. The Apple iPhone 6/6s/SE, the Google Nexus phones, and the Motorola Moto X Pure work on all four major carriers.
Shopping for an unlocked handset can be a bit tricky, since AT&T and T-Mobile stores don't stock them. If you're looking for one, Amazon, Best Buy Mobile, and the manufacturers' own online stores are good bets. In some cases, you can even unlock the phone you already own, although the particulars depend on the handset and carrier.
Our most recent Editors' Choice picks for unlocked devices include the Apple iPhone SE, the HTC 10, and the low-cost Blu Life One X. The iPhone SE gives you a world-class processor in a uniquely small, one-handed form factor. The HTC 10 has amazing audio and a durable all-metal body. The Life One X, meanwhile, delivers massive value for $149.
Ready to break free? Pick up one of these handsets and don't feel tied to your carrier any longer.
For more, see our Cell Phones Product Guide, and check out our lists of The 10 Best Smartphones and The Best Android Phones. If you're deciding on a carrier, take a look at How to Save Money on Your Cell Phone Plan.