Want to sell your iPhone 6? Do it now.

eBay statistics show that sales of older iPhones spike after a new version is released. But selling prices drop quickly.

Image: TechRepublic

The iPhone 7 is out now, and the time is right to offload iPhone 6 models for the best possible return. If past history is an indicator of future trends, a sales boom of the iPhone 6 is happening now:

Image: eBay

According to a spokesperson for eBay, "When the iPhone 6s debuted, the number of sold iPhone 6/6 plus devices increased by 23%. eBay's sales data showed that between August 1 and August 16 of this year, when rumors about the iPhone 7 were still swirling, one iPhone 6 sold every minute on the site.

I covered a similar topic last year when the Samsung Galaxy S6 came out; according to eBay, "in the 10 days after the Samsung S6 announcement event invitations went out to press on February 2, the number of Galaxy S5 models sold jumped nearly 65% on eBay, and the average selling price (ASP) rose nearly 30%."

SEE: Here's how much the iPhone 7 costs to make (ZDNet)

The selling boom doesn't last long, however, and prices generally start dropping within a few weeks. Between August and October last year, the average price for a used iPhone 6 dropped by $80 and the average price for a used 6 Plus dropped by $109. I spot-checked eBay what some of these models are selling for at present, and right now prices range from $299-$309 for a used iPhone 6 to $614 for a new iPhone 6s Plus.

Overall, here is a good breakdown of what these phones are selling for, on average:

Image: eBay

Statistics clearly show that iPhone 6 owners considering getting rid of their current devices in favor of an iPhone 7 need to strike while the iron is hot. To help facilitate the sale of older devices (both Android and iOS), eBay has launched a new program called Quick Sale.

This service allows potential sellers to get a quote on their phone based on manufacturer, model, wireless carrier, data capacity, color, condition and accessories. If it meets the criteria for Quick Sale (my Samsung Galaxy S5 didn't), it can be sold using this service, but if not it can be listed manually for sale on eBay (I guess I'll stick with my phone, which shows a trending price of $110.00).

Assuming it's eligible for Quick Sale, you can send your phone in. It will then be evaluated via a hands-on inspection and if it meets the criteria you'll be paid immediately via PayPal.

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The Quick Sale FAQ says that "phones in poor condition, older model phones, phones worth less than $100 customized or collector phones that are one-of-a-kind, illegal items including stolen property, items with removed serial numbers, and recalled items" are ineligible for Quick Sale. My Samsung Galaxy S5 certainly isn't stolen, so it must be considered an older model phone.

All in all, Quick Sale seems to be a good way to easily hand off old devices and get a fair value for them. It's not the only option, of course. Craigslist is one such resource, and iPhone 6 devices in my area are typically going for about $300-$400. Gazelle is another site and reports indicate the iPhone 6s / 6s Plus is selling for $350-$360 and lower. These model iPhones sold on Nextworth are yielding a better rate depending on carrier; they appear to be Verizon-centric, but less enthusiastic about T-Mobile products.

You could also use Apple's "trade up" program to get credit at any Apple store, or do the same thing at Best Buy. It's also usually possible to trade your old device in directly to your carrier when upgrading as well.

It can be depressing to find that a phone once valued at $500 when shiny and new has depreciated to a fifth of the original value, but as mobile devices continue to rapidly evolve, staying ahead of the curve with the latest technology can be a more valuable experience than currency.

Also see:
8 reasons why professionals should get the iPhone 7
Apple iPhone 7: The smart person's guide
Samsung Galaxy S6 launch provokes an eBay rush
Impact of iPhone 6 on iPhone 5 pricing and sales