The best ways to trade in your old smartphone so you can upgrade to the iPhone 11

You can also answer a few questions to get a more specific idea of what you'll get your phone. The quiz asks who made your phone, which model you have, and if its in good condition. For example, my iPhone XR in good condition would get me a $350 Apple gift card.

If I traded in my iPhone XR, I could get an iPhone 11 Pro Max for $749. Using Apple's trade-in estimates and current prices, you can find what you would pay for a new iPhone.

You can start the trade-in process with Apple right here.

Gazelle will pay you with a check, PayPal, or Amazon gift card after you fill out a questionnaire with similar questions to Apple's: if the phone works, what condition is it in, and a some other basic information.

After answering, you'll get an estimate and Gazelle will send you a box for shipping. If your phone matches your answer, you should be paid within 10 days. For my iPhone XR, Gazelle estimates that I would receive $400.

You can check out Gazelle's service right here.

According to Swappa, a fully functional iPhone XR with 256 GB of storage goes for $691 on average, or almost the price of a new iPhone 11.

Keep in mind that you have to actually find another user who agrees to buy your phone, but if you're willing to deal with that added hassle, you could get more money than on other trade in sites.

Check out how Swappa works right here.

Decluttr pays slightly more than other trade-in sites, offering $491 for my iPhone XR.

This is a good option if your phone is damaged at all — when I checked, Decluttr was offering $294.60 if my phone had "heavy wear and tear, such as scuffs, dents and deep scratches."

You can check out Decluttr for yourself right here.

Major phone carriers often offer some sort of incentive for trading in your phone and adding a new device to your phone plan.

While Verizon, Sprint, AT&T, and T-Mobile are all promoting the iPhone 11 on their sites right now, they haven't revealed any trade-in incentives.

We'll likely find out more when the iPhone 11 becomes available to order on September 13.