So our experience with travelling overseas with the iPad (admittedly not to turkey) is that it costs 25$ for 25 MB or something and it was totally worth it for us.
I doubt she had the 4g version of ipad bc it costs like $100 more plus unless you use ipad alot in car it is generally not worth the money to pay $15 a month for access
So she probably used wifi only and that likely would have been free or cheap in an Internet Cafe