With only a few days left before the rumored Sept. 10 launch date of the new iPhone devices, retailers are already ramping up their services to accommodate the expected boost of consumers.

Trade-in programs have been a common service in gadget retail stores - both online and in brick - in an aim to help cut the price tags of new devices considerably for buyers. One of the most popular sites to offer this kind of service online is Gazelle.

Now, Apple Insider reports that the online gadget retail store is pushing its trade-in program further by offering an extended price lock-in period.

"Customers looking to upgrade their iPhone this fall can now lock in a guaranteed trade-in price through Oct. 15 at Gazelle, ensuring they will receive the same amount after Apple's anticipated Sept. 10 product announcement," Apple Insider wrote on its site.

According to the report, Gazelle announced the offer just this Monday (Aug. 26), allowing consumers to keep their devices until the new Apple iPhone drops but still get the same trade-in price before the new smartphone is released.

Apple Insider writes:

As is usually the case, it's expected that the trade-in values of current iPhone models will drop once Apple announces its latest models, but customers can avoid any further price drops once the Sept. 10 event passes.

For example, owners of a 16-gigabyte AT&T iPhone 5 in "flawless" condition can lock in a payment of $330. And a 16-gigabyte Verizon iPhone 4S in perfect condition is worth $185.

One Gazelle's website a banner ad reads "Lock-in today's iPhone price until October 15th."

"Our price lock promotion allows savvy consumers to maximize the value of their old iPhone and lets them wait until after the new iPhone is here to send in their old one," Gazelle's chief marketing officer Sarah Welch told the site. "In many cases we pay enough to cover the full cost of upgrading to a new phone. We've been doing this quietly for years to help our customers get great value despite the potential challenges of getting their hands on a new iPhone in the early days of a launch, and we're delighted to extend the price lock program even further this year."

As seen on Gazelle's website, the company offers the trade-in pricing guarantee for all iPhone types except the first generation smartphone. It also accepts iPhones from all major carriers, but offers higher prices for those that are Factory Unlocked.