The much anticipated iPhone 4S is officially upon us and pre-orders are selling out record quantities. If you have already ordered your iPhone 4S you should actually start receiving it this week, and if you haven’t what are you waiting for? With a much faster processor and improved camera, Apple’s newest edition surely won’t disappoint. So that begs the question. What are you going to do with your old iPhone 3GS? Sell it online of course. If you sell your iPhone 3GS you’ll be on your way to paying off that new iPhone 4S in no time.

Choosing the right place to sell your iPhone 3GS is of course a little tricky. You can always use eBay, but that tends to be a hassle and there is no shortage of iPhones on that site. Instead try leveraging a Boston based startup that only exists to get you cash for your electronics in a efficient and trustworthy way.

I spent the time trying a few different options to find the best choice when trying to decide where to sell your iPhone 3GS. Here are the results from Gazelle, Nextworth and YouRenew.

To make sure we achieve consistent results, I am choosing a Black 32GB iPhone 3GS in ‘good’ condition.

Gazelle:

Current Offer: $143. Gazelle offers to lock in your price for 30 days, which is huge!

Payment: Amazon, Check or Paypal

Shipping: Gazelle pays for shipping.

Notes: Gazelle also recently came out with a new iPhone app, that will actually let you sell your iPhone from your iPhone.

Nextworth:

Current Offer: $155

Payment: PayPal, Target Gift Card or a Check in the mail

Shipping: Nextworth pays for shipping.

Notes: NextWorth not only provides free shipping, but also has partners nationwide that allow for in-store exchanges. This option allows you to not only avoid shipping and waiting for a check, but also to not only sell, but exchange as well. This way you can upgrade in one stop instead of having to overlap the new and old items.

YouRenew:

Current Offer: $120

Payment: PayPal or Check by Mail

Shipping: YouRenew pays for shipping

After sorting through all three options for a place to sell your iPhone 3GS it looks like the winner is clear. In order to get the most money for your used iPhone 3GS, Nextworth is the place to sell it. You can get gift cards, a check in the mail or paid on PayPal right away.