Question : How long do most people stay in Tunis?
Answer : Of course you're not most people, but if you were, you'd stay roughly 12 days.
Question : Have you considered flying out of an airport besides Sabiha Gokcen International Airport (SAW)?
Answer : Lucky for you, there is another airport near Istanbul. Istanbul Ataturk Airport (IST) is 26 miles away, and over the upcoming two months, flights are being booked 50% cheaper than flights from Sabiha Gokcen International Airport.