It depends on what you eat, but there's far more than lahmacun on the diet. Now, you're probably sticking to Turkish food (Chinese is going to start at 15TL, the equivalent of 8.5 dollars or so) but I'm regularly eating decent food for the 3-8 dollar (2.5-6 euro) range, with drink.

Great produce is also ridiculously cheap here, which makes cooking a much better deal.