Nokia has begun offering its Lumia line of smartphones at discounts -- and even for free -- in the U.S. Amazon.com is selling the month-old 920 model for $39 with an AT&T contract, compared with its original $99 price tag. Verizon Wireless is giving away the Lumia 822, while T-Mobile is not charging for the Lumia 810 under contract. Nokia noted that smartphone promotions are "fairly standard" during the holidays.