How to get the most money for your old iPhone

It's that time of year again! This week Apple announced its new iPhone, which went up for pre-order yesterday and becomes available on September 25.

That means there's an opportunity to make some decent money if you plan on upgrading and don't need to hold on to your old device.

There are tons of ways to trade in your old iPhone, and we took a look at some of the most popular trade-in platforms to see how the trade-in values compared at each.

How we tested

To get these results, we compared the trade in value at Best Buy, Apple, Gazelle, and Amazon. For continuity purposes, we looked at the value for a 16GB iPhone across each platform. To get an idea of how the value differs between a carrier-locked phone and unlocked phone, we looked at the value for both a 16GB iPhone on Verizon's network and a 16GB unlocked iPhone. We also assumed that the phone is in good condition, which means that the phone shows signs of normal wear and tear, but isn't significantly damaged in any way.

It's important to remember that these are just estimates intended to illustrate how the trade-in value differs between each retailer. The monetary value of your iPhone is always subject to change depending on factors like its condition, storage capacity, which carriers it's compatible with, and even its color.

Gazelle

Gazelle offers you about the same amount of money you'd get if you traded in your phone with Best Buy or Apple. In some cases, the value was higher (i.e. you can get $75 back for an iPhone 5C in good condition, versus $65 at the Apple Store), but for the most part the difference was only about $10 or so. What makes Gazelle a more attractive option, however, is the convenience aspect. If you trade in your phone through Gazelle, you can choose to get paid via a check, PayPal, or Amazon store credit. Other platforms only give you credit toward that particular retailer.

Here's a snapshot of what you might get through Gazelle if you trade in one of Apple's more recent iPhones:

• iPhone 5 -$90 for a Verizon iPhone; $95 for an unlocked iPhone
• iPhone 5C -$75 (for Verizon or unlocked)
• iPhone 5S - $150 (for Verizon or unlocked)
• iPhone 6 - $310 for a Verizon iPhone; $320 for an unlocked iPhone
• iPhone 6 Plus - $335 for a Verizon iPhone; $345 for an unlocked iPhone

Apple

If you trade in your iPhone through Apple's Reuse and Recycle program, you can get a decent amount of money back for your old iPhone. In most cases, Apple's estimates indicated that you'd get more money back through its program than you would selling your phone through Gazelle (except for the iPhone 5C). But, you only get Apple credit back for your purchase while Gazelle's options are more flexible. Here's a look at what you might get if you trade your iPhone in through Apple:

• iPhone 5 - $90 (for both Verizon or unlocked)
• iPhone 5C - $65 (for both Verizon and unlocked)
• iPhone 5S - $165 (for both Verizon and unlocked)
• iPhone 6 - $325 (for both Verizon and unlocked)
• iPhone 6 Plus - $375 (for both Verizon and unlocked)

Best Buy

Best Buy's prices were mostly in line with what Gazelle and Apple offer, with a difference of between $5-$10 here and there. The main discrepancy seems to be that Best Buy offers much more money for phones on Verizon's network. It's unclear why, but in every instance the monetary value for a phone on Verizon's network was significantly higher than the unlocked value. When you trade through Best Buy, you only have the option of getting store credit in return. Here's a look at the prices we found on Best Buy's website:

• iPhone 5: $110 for a Verizon iPhone; $80 for an unlocked iPhone
• iPhone 5C: $92 for a Verizon iPhone; $75 for an unlocked iPhone
• iPhone 5S: $200 for a Verizon iPhone; $155 for an unlocked iPhone
• iPhone 6: $386 for a Verizon iPhone (no unlocked option)
• iPhone 6 Plus: $435 for a Verizon iPhone (no unlocked option)

Amazon

Amazon seemed to offer the best trade-in values when compared against Gazelle, Best Buy, and Apple. According to the estimates on Amazon's trade-in store, you could get well over $100 for an iPhone 5 in good condition, which is more than you'd get through any of the other platforms. You'd get Amazon credit in return for your trade in. Here's a look at what Amazon has to offer (Note: The values varied on Amazon more than any other platform, so we included a price range for some of the phones listed below):

iPhone 5 - $169 for a Verizon iPhone; $153-$169 for an unlocked iPhone

iPhone 5C - $140-$155 for a Verizon iPhone; $150-$156 for an unlocked iPhone

iPhone 5S - $227-$240 for a Verizon iPhone; $253 for an unlocked iPhone

iPhone 6 - $387-$410 for a Verizon iPhone; $386-$420 for an unlocked iPhone

iPhone 6 Plus - $387-$442 for a Verizon iPhone; $462-$486 for an unlocked iPhone

Conclusion

Ultimately, Amazon offers the best trade-in value of the platforms we compared. Best Buy and Apple offered about the same in terms of value, but Best Buy seems to offer more for phones that work on Verizon's network. If you care about getting straight cash in return for your phone, you'll want to use Gazelle. You may not get as much money back as you would through Amazon, but you have the choice of getting cash rather than store credit.

Disclosure: Jeff Bezos is an investor in Business Insider through hispersonal investment company Bezos Expeditions.