This is in Kharader, one of the oldest parts of Karachi where I grew up - and so did the founder of Pakistan (M Ali Jinah). At PKR16.00 (USD0.20) this is surely one of the cheapest burgers in the world. A lot of people in my family and friends, including me, believe this may also be the tastiest burger in the world.
The patty is made of potato and vegetables, then dipped in battered egg and pan fried in vegetable oil. It's then put in a traditional bread with sauces made of yogurt and mint, and lots of onions. Mostly healthy stuff except for the oil, but not the most hygienic in the world :)
I have seen this stall sell exactly the same burger since I was five (1970). As kids, we used to buy from the old man who died a few years ago, but his son has taken the family business to another level by taking up a small room behind the stall which can seat up to 10 people. He sells an estimated 2000 burgers a day!