Hi there, best thing to do is dial 1045 before any national or international calls landlines and mobiles and this reduces the cost of your calls. When I phone the UK, normally on the phone about 20-30 mins and I've never been more than about a lira for the call!
You will get 2 bills from Turk Telecom, one for the normal calls and one for all your 1045 calls. Our monthly bill is never more than 20 lira for all our overseas calls and we call to the UK at least twice a week.
For anyone calling you from the UK, if they go through budgetcom they can get calls to a Turkish landline for 1p a minute or 7p a minute to call a Turkish mobile.
Hope this helps.
Denise