How To: Upgrading to iPhone 6? Trade in Your Old iPhone for $400

Apple is set to unveil the iPhone 6 on September 9th, and shortly thereafter carriers like AT&T and Verizon Wireless will begin selling them online and in stores. So, if it's time in your contract for a device upgrade, it's time to start thinking about trading your current iPhone in for up to $400 in value.

This year, some companies are even letting you lock in sell or trade-in prices for your current iPhone right now. For instance, Gazelle will let you "sell" your iPhone 5, 5C, or 5S to them right now for today's iPhone prices (which are usually higher than after a new model actually comes out), as long as they get the device by October 10th.

Amazon.com is also offering locked-in prices for trading in older iPhones, but instead of getting cash back, they'll give you Amazon gift cards, which might be a better deal if you tend to buy a lot from Amazon, or purchase a lot of Kindle books or Instant Videos.

Amazon.com: Get Amazon Gift Cards

As just mentioned above, Amazon is letting you trade in iPhones for gift cards, up to $400, but in order to start the trade-in process, you have to find the product page for your particular iPhone model, size, carrier, and color.

To help you out, hit up one of the links below to add your specific iPhone to your shopping cart. Prices in (parentheses) are the max payouts for "Like New" conditions.

iPhone 5 - BLACK

• AT&T - 16GB ($232); 32GB ($234); 64GB ($242)
• Sprint - 16GB ($182); 32GB ($229); 64GB ($259)
• Verizon - 16GB ($236); 32GB ($207); 64GB ($338)
• Unlocked - 16GB ($251); 32GB ($271); 64GB ($182)

iPhone 5 - WHITE

• AT&T - 16GB ($234); 32GB ($228); 64GB ($271)
• Sprint - 16GB ($221); 32GB ($236); 64GB ($311)
• Verizon - 16GB ($185); 32GB ($240); 64GB ($331)
• Unlocked - 16GB ($259); 32GB ($283); 64GB ($253)

iPhone 5s - GOLD

• AT&T - 16GB ($326); 32GB ($343); 64GB ($223)
• Sprint - 16GB ($287); 32GB (N/A); 64GB ($400)
• T-Mobile - 16GB ($340); 32GB ($375); 64GB ($400)
• Verizon - 16GB ($369); 32GB ($400); 64GB ($400)
• Unlocked - 16GB ($394); 32GB ($400); 64GB ($400)

iPhone 5s - SILVER

• AT&T - 16GB ($302); 32GB ($351); 64GB ($400)
• Sprint - 16GB ($275); 32GB (N/A); 64GB ($400)
• T-Mobile - 16GB ($375); 32GB ($400); 64GB ($346)
• Verizon - 16GB ($319); 32GB ($400); 64GB ($400)
• Unlocked - 16GB ($394); 32GB ($400); 64GB ($400)

iPhone 5s - SPACE GRAY

• AT&T - 16GB ($316); 32GB ($347); 64GB ($400)
• Sprint - 16GB ($267); 32GB ($327); 64GB ($400)
• T-Mobile - 16GB ($368); 32GB ($400); 64GB ($345)
• Verizon - 16GB (N/A); 32GB ($383); 64GB (N/A)
• Unlocked - 16GB ($385); 32GB ($400); 64GB ($400)

Gazelle.com: Get Cash Back

Gazelle is a little easier to navigate than Amazon, and color is no concern to them. Just head to their website, select your model iPhone, your carrier, your size, and then the condition to see the cash value, up to $325. If it's good for you, hit the "Paid" button to begin cashing out.

Gazelle provides you with shipping material for free, and once they get your device, you'll be paid with either an Amazon gift card (though, if you want that, you should opt for the Amazon trade-in program), PayPal transfer, or check.

The locked-in prices will remain the same until September 9th when the iPhone 6 is announced.

Apple.com: Get Apple Gift Cards

Just like Amazon, Apple is offering a trade-in service for your old iPhone in exchange for Apple gift cards, though no prices are locked in. But, having Apple gift cards might be better than Amazon ones, especially if you always find yourself saying no to paid apps in the iOS App Store.

Just head to Apple's iPhone Recycling page, powered by Brightstar, to begin the process. However, Apple is only accepting iPhone 4, 4S, and 5 right now, for up to $225, and there's no word on when they'll begin accepting the 5C or 5S. So, if you have a newer device to trade in, Amazon or Gazelle might be your best bet.