If your'e looking for a really decent meal in Edinburgh for under £5 check out Edinburgh Mosque Kitchen. Extremely good food, massive portions and diverse menu with veggie options as well. Basic outdoor seating with plastic cups and plates, takeaway boxes available as well. Does BBQ chicken on saturdays. Everything cooked using olive oil.

Opens from around 11am till 7pm

Located near the Gilded Balloon Theatre
50 Potterow
Edinburgh
EH8 9BT.

There are a list of restaurants available at Rooms in Edinburgh for all cusines which is pretty handy. I prefer so good old fashioned pup grub myself!