Buying a Used iPhone? 10 Tips to Avoid Getting Ripped Off

There may be more to buying a used smartphone than its price — but not much. Otherwise, everyone would buy a new phone, right?

But there's more to shopping for a used smartphone than just dollars and cents. In addition to looking for cost savings on the initial outlay — you could slash up to 50 percent off the price — you'll want to consider product cycle, age, model, condition and carrier as you shop for a used phone from a reseller, carrier or other reputable marketplace.

Credit: Jeremy Lips / Tom's Guide

(Image credit: Jeremy Lips / Tom's Guide)

How do I know? I just shopped for used iPhones on seven reseller and e-commerce sites, and then resold those devices to rank the best services for selling your used smartphone. That experience revealed the most important things to keep in mind when mulling a used-smartphone purchase.

To start, it helps to know what you're shopping for. There are three categories of used phones: used, certified pre-owned and refurbished. A used phone is just that — used, as is, with all flaws hopefully (but not necessarily) disclosed. Generally, a certified pre-owned phone has undergone a certain amount of testing and has been repaired to function properly. A refurbished device has been repaired to a "like new" condition. Certified pre-owned and refurbished phones often come with a warranty and can be sold by third parties.

MORE: The Best and Worst iPhone Trade-In Deals

Popular marketplaces such as Glyde, Swappa, Amazon, Best Buy, GameStop and others inspect the phones they accept for trade-in, but they offer refurbished phones only if a seller posts one. If you're looking for a refurbished phone, do a specific search for one, and be sure to check the Big Four carriers.

With brand-new iPhones expected to hit the street in September, Apple fans may want to get their act in gear. But the following tips apply equally to all mobile devices, whether they're powered by iOS or Android.

1. Know when to buy.

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The resale price of a pre-owned phone depends on the device's age, with its value dropping over time. The best time to check prices for current and previous models is when a new generation of your favorite brand emerges and thus the value of older versions declines.

2. Research prices.

There's no easy way to calculate the exact value of the handset you want to buy, but you can get a decent idea of the general prices people are paying by spot-checking resellers and carriers. Luckily, once you set your sights on a particular model or two, it does not take long to track a handful of sites to compare prices.

3. Buy from your carrier.

Most wireless carriers sell certified pre-owned phones and/or refurbished phones. While those devices may be more expensive than comparable models available through resellers, you have the advantage of knowing that the phone will work with your carrier. You also don't have to worry about inadvertently buying a stolen device.

4. Make sure your reseller has a return policy.

A stated return policy lets you return the phone if it does not meet your expectations. Swappa, a marketplace that matches smartphone buyers with sellers, verifies each listing and has a mechanism for returning items that do not meet expectations. PayPal consumer protections can also facilitate refunds to dissatisfied customers.

5. Note the phone's overall condition.

If you're considering a used phone, then assume you are going to live with a few minor scratches or dents from ordinary wear and tear. Even so, pay particular attention to physical descriptions of phone listings. Try to buy from vendors that post genuine photos of the phone being sold, as opposed to generic product images. "Mint condition" to one person can be just OK to another, and that's why it's important to compare only analogous descriptions. Be clear about what is acceptable to you for the price, because in most cases, you will not get a warranty when you buy a used phone.

6. Test your phone immediately.

When your phone arrives, inspect it to make sure it's in working order. Check for dents, scratches, water and camera lens damage, and screen cracks. There should be no lines running through the screen or any color bleeding. Shine a flashlight on the phone and into its open ports and SIM card slot to check the white liquid contact indicators for corrosion from water damage.

With phones you can open, check for corrosion on the battery and inner body. (You'll see a yellow or pink color.) Open all flaps, covers and ports, and plug in your headphones, charging cord and SIM card or microSD card (if applicable), to make sure everything works. Send a text, make a call, shoot a picture and browse the web to ensure the SIM card is working. Test the volume buttons and speaker. Check all included accessories too, including earbuds, the power cord and the wall charger.

7. Do a service code check.

Running a service code test — a handy on-screen diagnostic tool — will alert you to any invisible problems with your touch screen, speakers, camera, vibration, sensors and more. Each phone brand has a service code that lets you check aspects of the hardware and software. Different brands have different codes, so find the one for your particular phone via a Google search: Search for the name of the phone model and the words "service code." If you're buying a used iPhone, check out the free Test and Check for iPhone app, which offers a general checklist of immediate physical and internal tests — screen brightness, color, touch-screen sensitivity, accelerometer and more — to conduct on your phone.

8. Make sure it is not reported lost or stolen.

Buying from carriers and reputable resellers is the best way to ensure that your phone is legit because they'll check for lost or stolen phones before they put a device on sale. Despite that, it's a good idea to observe the exact company policy regarding how your reseller checks the identifier (ESN or IMEI) of the phone you want to buy, which also reveals whether the phone will work with your carrier.

You can check this online, in a store or with customer service. Do a free IMEI or ESN test on Swappa's website, even if you don't buy a phone there. You can also check the IMEI site.

9. Consider battery life.

Some Android models let you swap out an old battery, but the iPhone does not. If you're looking into a secondhand iPhone, consider that the battery may not hold a charge as well as it did when it was new. Because you're buying your phone from a reputable merchant, test out the battery over a couple of days to see how long it holds a charge. For phones that let you replace the battery, make sure the resident battery is the original made for the phone and not an inferior third-party replacement.

10. Beware of network locking.

Be sure to buy a phone that is either compatible with the network you intend to use — GSM for AT&T and T-Mobile, CDMA for Sprint and Verizon — or arrives unlocked.

Jackie Dove

Jackie is an obsessive, insomniac tech writer and editor in northern California. A wildlife advocate, cat fan, and photo app fanatic, her specialties include cross-platform hardware and software, art, design, photography, video, and a wide range of creative and productivity apps and systems. Formerly senior editor at Macworld and creativity editor at The Next Web, Jackie now writes for a variety of consumer tech publications.