People camp out overnight and wait for hours outside their favorite shops on Black Friday for good reason: amazingly hard-to-beat deals that come only once a year. With new iPhone 7 released just this year, Black Friday is definitely a time to go with deals announced by AT&T, Best Buy, Target, Verizon, and Walmart.  

Phone upgrades to iPhone 7 and iPhone 7 Plus are currently available for postpaid users for an additional $200. But on Black Friday, the average saving is $250 for an upgrade. A total turnaround of cards just by timing a purchase.

Black Friday occurs annually on the first Friday after Thanksgiving. It is the biggest shopping bonanza in the U.S. that it's also marked as a public holiday in some states.

As one Black Friday fan says, gift cards are key to getting the best deal. Some carriers and retailers encourage users to switch, offering them discounts of up to $250 plus monthly payment incentives. Then, in addition to this already big saving, a gift card can also be used upon checkout.

It is also not necessary to line up or to camp overnight to get the best Black Friday iPhone deal, as most of the biggest retailers offer transparent deals on their sites up to two weeks before Black Friday. On Target, Best Buy, and Walmart's sites, a $250 gift card is currently offered plus more deals that will be revealed on the day itself.

However, some see the best deals on the day itself and advice consumers not to bother buying pre-Black Friday deals online. Amazon is an exception though, as the retail giant starts its own Black Friday 13 days before the day itself and publishes its deals online.

Telco retail giants AT&T, Best Buy, Target, Verizon and Walmart have already published their Black Friday deals on their sites, and here is a rundown on their offers:

AT&T: savings of up to $649.99, with the biggest saving deal on switching to this carrier, combined with trading in an old iPhone.

Best Buy and Target: savings of up to $250, with an additional gift card provided that can be used for monthly payments. Deal is available starting on Thanksgiving Day.

Verizon: savings of up to $300, given that a customer trades in an old iPhone.

Walmart: savings of up to $250, with an additional gift card for monthly payments. Deal is available starting on Thanksgiving Day, and appointment in-store is necessary on Thursday from 6:00 pm.

Trading an old iPhone is a good option for down payment instead of cash. Many carriers, especially on Black Friday, accept an old iPhone and price them accordingly depending on the phone's condition.