How to Buy a Smartphone in the US: Carriers, Unlocked Phones and Trade-Ins
Buying a phone in the US means choosing a device, a carrier and a way to pay at the same time, and the carrier deal often costs more than it looks. This guide explains unlocked versus carrier phones, how installment plans and trade-in credits really work, and what to check before you sign.
Quick answer
Buying a phone in the US means choosing a device, a carrier and a way to pay at the same time, and the carrier deal often costs more than it looks. This guide explains unlocked versus carrier phones, how installment plans and trade-in credits really work, and what to check before you sign.
In this article
Buying a smartphone in the US is really three purchases bundled into one: the device, the wireless plan and the financing. Carriers are very good at making the bundle look cheap on day one, and very good at making it expensive to leave. The way to come out ahead is to separate the three decisions, price each one over the time you will actually keep the phone, and only then decide whether a carrier deal is worth the strings attached.
Step one: decide how long you will keep the phone
Everything else follows from this. If you replace your phone every two years, carrier promotions built around 24-month credits can make sense. If you keep a phone for four or five years, what matters most is how long the manufacturer will deliver software and security updates, and whether the battery can be replaced at reasonable cost.
Before shopping, check the maker's published update commitment for the model you are considering. Apple, Google and Samsung all state support periods for their phones, and they differ by brand and by model. A cheaper phone with a short update window can end up costing more per year than a pricier one supported for longer.
Unlocked versus carrier phones
An unlocked phone works on any compatible US network. You buy it outright, or finance it through the manufacturer or a retailer, and you are free to move your number to another carrier at any time.
A carrier phone is sold by AT&T, Verizon, T-Mobile or one of their brands, and is locked to that network until conditions are met, usually that the device is paid off and the account is in good standing, sometimes plus a minimum period of active service for prepaid phones.
| Unlocked phone | Carrier phone | |
|---|---|---|
| Upfront cost | Full price, or third-party financing | Often $0 down on a monthly installment |
| Switching carriers | Any time | After the phone is paid off and unlocked |
| Promotions | Occasional retailer discounts | Large trade-in and "free phone" deals, tied to plans |
| Software | Clean manufacturer software | May include carrier apps |
| Resale value | Generally higher | Lower while locked |
Unlocking rules are set by each carrier's policy, within commitments the industry made to the FCC, and the FCC keeps a consumer guide to how unlocking works. Ask for the carrier's current policy in writing before you buy if you think you might switch.
How carrier installment plans work
Most phones sold by US carriers today are financed through a device payment plan: the full retail price divided into equal monthly payments, typically over 24 or 36 months, with no interest. The payment appears on your monthly bill alongside the plan.
Three things matter more than the monthly number:
- The full retail price. It is printed in the agreement. That is what you owe if you leave early.
- The term. A 36-month plan lowers the monthly payment but keeps you tied to the carrier for three years.
- Credit checks. Financing usually involves a credit check, and the carrier may require a down payment if your credit profile is thin.
Trade-ins and "free" phones: the bill credit catch
The headline offers ("get the new phone on us") almost always work the same way. You trade in an eligible phone, sign up for or keep a qualifying plan, and the carrier gives you monthly bill credits that cancel out the installment payment, spread over the whole term.
This has consequences worth spelling out:
- You only get the full value if you stay for the full term. Cancel the line, port your number out or pay off the device early, and the remaining credits usually stop.
- The qualifying plan may cost more than you need. Promotions are often limited to the carrier's premium unlimited tiers. Compare the extra plan cost over the term with the value of the credits.
- Trade-in condition is judged after you send it in. A cracked screen or a device that doesn't power on can drop the credit to a fraction of the advertised value.
- The offer has an end date. Credits can take one or two billing cycles to appear; keep screenshots of the offer page and your order confirmation.
Selling your old phone privately or through a reputable buyback service can sometimes pay more in cash than a carrier credit, especially on unpromoted models. Compare both before you decide.
Choosing the network, not just the deal
The three national networks, AT&T, Verizon and T-Mobile, each have areas where they are strongest. Coverage maps are a starting point, and the FCC's National Broadband Map lets you check mobile coverage reported for your address. Better still, ask neighbors and coworkers which carrier works inside their homes and offices, or try a prepaid line for a month before committing.
Many lower-cost brands, known as MVNOs, run on those same three networks. Some are owned by the big carriers (Visible by Verizon, Cricket Wireless by AT&T, Metro by T-Mobile and Mint Mobile by T-Mobile), while others, such as Google Fi and cable companies' mobile services, buy network access wholesale. Bringing an unlocked phone to one of them is often the cheapest way to run a phone in the US.
Where to buy
- Directly from the manufacturer. Apple, Google and Samsung sell unlocked phones online and often offer their own financing and trade-in programs that don't tie you to a carrier.
- Big-box retailers. Best Buy, Walmart, Target and Costco sell both unlocked and carrier models; read the listing carefully to see which you are getting.
- Carrier stores and websites. Best for carrier-specific promotions, but be ready for add-ons such as insurance, accessories and activation fees.
- Refurbished. Manufacturer-certified refurbished phones carry a warranty and are a solid way to save. With third-party refurbishers, check the grading system, warranty length and return window.
Before you sign: a checklist
- Confirm the phone supports your carrier's network and, if your carrier requires it, works with eSIM.
- Write down the full retail price, the term and the monthly payment.
- If there is a promotion, read who qualifies, which plan is required and what happens if you leave early.
- Ask about activation fees, upgrade fees and any recurring add-ons on the order.
- Check the return window. Carriers and retailers set their own, and some charge a restocking fee.
- Back up your old phone before trading it in, then sign out of your accounts and erase it.
- Keep every confirmation email until the final bill credit has posted.
Accessories and protection
A case and a screen protector are cheap insurance. Device protection plans from carriers are optional; compare the monthly fee and per-claim deductible with what a single screen repair would cost, and check whether your credit card or homeowner's or renter's insurance already covers phones. Manufacturer plans such as AppleCare+ or Samsung Care+ can be bought separately from the carrier.
The best deal is rarely the one with the biggest headline. It is the combination of a phone you will happily keep, a network that works where you live, and a payment arrangement you can walk away from without penalty if your needs change.
Frequently asked questions
Is it cheaper to buy an unlocked phone or a carrier phone?
It depends on how long you keep the phone and whether you were going to stay with the carrier anyway. A carrier promotion can beat the unlocked price if you would have stayed for the full credit period, but it usually requires a specific plan and you lose the remaining credits if you leave early. Add up the plan cost over the whole term, not just the phone price, before comparing.
What happens to my trade-in credits if I switch carriers?
Most US carrier trade-in deals are paid as monthly bill credits spread over the length of the installment agreement, often 24 or 36 months. If you cancel the line or pay off the phone early, the remaining credits typically stop and the outstanding device balance becomes due. Read the promotion terms for the exact rule before you trade in.
How do I know if my phone is unlocked?
On an iPhone, go to Settings, then General, then About, and look for a line that says No SIM restrictions. On Android the location varies by maker, but the simplest test is to insert or add a SIM or eSIM from a different carrier and see whether it connects. Your carrier can also confirm the lock status on request.
