I thought I saw a reference to this a few weeks ago but couldn't find it by searching.
I notice BIM are making a big "push" to get people to sign up for one of their sim cards.
In my experience whatever BIM do it is normally "cost effective" so I asked the assistant in our local store was it contract or pay as you go - she said "kontract yok"
which made me more interested.
The leaflet says you need your kimlik and a photocopy of your kimlik and seems to be saying the big selling point is
every 6 seconds cost 1 kurus - and it appears you to up your card with 20 lira at the store but it also seems to be saying (I am probably wrong here) you can make 80 x 2.5 minutes calls with your 20 lira?
Now if that is right is sounds much better than Vodaphone - can anyone tell me more
See:
http://www.bimcell.com.tr/nasil-bimcellli-olunur.html