ISTANBUL — Smartphones were once an extravagance in Turkey and mobile Internet plans cost a fortune. But now you can find used iPhones at the flea market in front of the historic gates of Istanbul University and a two gigabyte Internet package that will run you over TL 50 in the U.S. will only cost you TL 10-15. Smartphones have become a normal part of daily life. Today's Turks can't go one day without checking into their favorite cafés on Foursquare, updating their Facebook statuses, sharing their selfies on Instagram or posting their thoughts on Twitter. With Turkey's massive number of social media users from one mobile operator alone (these figures don't account for computer access or Turkey's two other main operators, Vodafone and Turkcell), these social media sites among others generate many millions of dollars in revenue from Turkey.