If you still haven't picked up the new iPhone 6 or 6 Plus, you may be pleased to hear that there are still some exciting discounts and sales going on through carriers Verizon, T-Mobile, Sprint, and AT&T, and retail stores Wal-Mart, Best Buy, and Sam's Club.

While many trade-in deals expired during the new Apple phone's launch week, you can still find some hefty deals out there.

Verizon

The popular carrier is offering trade-in deals for up to $300 on your old iPhones with a 2-year contract. A handy appraisal tool on Verizon's website will tell you how much you can expect to get for your old phone, depending on model, features, etc. This promotion ends tomorrow, October 15.

Related: Galaxy Note 4 vs iPhone 6 Plus: A Comparison of Specs, Camera and Best Features 

AT&T

AT&T is offering a similar promotion to Verizon's deal with up to $300 value on trade-ins, but this offer lasts until October 31. With both Verizon and AT&T, you sign-up for the deal by purchasing the iPhone 6 of your choice and a 2-year contract, and then send in your old phone through the mail.

Sprint

Sprint is offering a trade-in deal for up to $350 if customer transfers their existing phone number over to a new Sprint Simply Unlimited Plan by October 31. The customer then gets a Visa Prepaid Card with the trade-in amount which could take up to 12 weeks to receive.

T-Mobile

T-Mobile guarantees the "best trade-in value in wireless" by offering to not only beating a competitor's deal, but they'll also pay your early termination fees on the previous carrier. This equates to "up to" $350 per line for up to five lines when you switch to T-Mobile. Check out T-Mobile's trade-in site to get a true estimate of what your phone is worth. No expiration date is listed for this deal.

Wal-Mart and Sam's Club

Wal-Mart is offering "double the trade-in value" on older iPhones as long as the phone works and has no cracks on the display. The catch, of course, is that Wal-Mart will not pay out more than $200 in this double-value deal, but will pay your phone's value if it's worth more than $200. This deal expires on October 18.

A brighter side of this deal is that both Wal-Mart and Sam's Club are offering the 16GB iPhone 6 at an impressive discount anyway ($179 Wal-Mart, $177 Sam's Club), so overall, the deal may work out better, even with the lower trade-in value.

Best Buy

Best Buy lets you trade-up several items in their inventory, but the big box retailer is offering a straight $200 trade-in value for any qualifying smartphone that can be used toward the purchase of any other new phone. This is a good deal if you're looking to get out of your Android phone into an Apple phone, or vice versa, but not the best deal for an iPhone-to-iPhone upgrade. This offer lasts until October 16.