Trade-in programs by major mobile carriers offering the iPhone 6 and the iPhone 6 Plus are still widely available. This will allow customers to trade in their old iPhone devices for the value and convenience that they aim to obtain. Major mobile carriers that still offer trade-in deals for the recently launched iPhone 6 variants include Verizon Wireless, AT&T, T-Mobile, and Sprint.

For Verizon Wireless, the company is currently offering gift cards worth $200 for customers who trade in an iPhone 4, 4S, 5 or 5C. A gift card worth $300 will be offered for those with an iPhone 5S. Both existing and new Verizon customers are eligible to avail of the promotion. Customers should take their current iPhone to a Verizon store or accomplish a request online on or before Sept. 30. After receiving a new iPhone, customers should be able to send a receipt and claim their gift card by Dec. 1.The trade-in promotion, however, is not applicable for customers with current data plans.

For AT&T, a similar trade-in deal is being offered until Sept. 30. Customers can trade in their iPhone 4,4S, 5 or 5C for $200, while the iPhone 5S will offer customers $300. The offer can be availed by both current and new customers, and the iPhone to be traded in can be from AT&T or other carriers.

Meanwhile, T-Mobile is focusing on beating any trade-in offers from other carrier competitors. If a customer makes a trade-in with T-Mobile and recognizes a more valuable offer from Verizon, AT&T or Sprint, T-Mobile will offer a deal that is $50 more. The mobile carrier, however, has not commented as to when the offer will last, although the Verizon and AT&T deals are expected to end this September.

Finally, Sprint is putting forward its Buyback program that guarantees lower prices for its trade-in deals compared with other carriers. As such, following the footsteps of the T-Mobile program, Sprint will be making such offer available until the end of this month when the Verizon and AT&T promotions expire. The company is also proposing a deal with which a special iPhone 6 $200 credit will be offered to enable customers to obtain an iPhone 6 (16GB) at $199.99. Such deal is expected to end on Oct. 31, 2014.

All in all, these offers from major mobile carriers have been deemed ideal, even for owners of older iPhone models. Compared to Gazelle's offering of $15 for a Verizon iPhone 4 16GB model and $265 for a Verizon iPhone 5S 16GB, the current trade-in deals offered by major mobile carriers are more than special.