If you plan to conquer Istanbul in 72 hours or less, then you might like to check out the feasibility of buying the 85TL Museum Pass. The pass gives you queue-jumping privileges and discounts on some museums, attractions, and tours around town for up to 72 hours once the pass is activated at the first museum. Before buying, do check if the locations listed are where you want to go.
To give you an idea of potential savings, as of October 2013, the price of a single entry ticket (per person) were: * Chora Museum - 15TL * Hagia Sophia Museum - 25TL * Topkapı Palace Museum - 25TL (Harem is 15TL) * İstanbul Archaeological Museum - 10TL * İstanbul Mosaic Museum - 8TL * Museum of Turkish and İslamic Arts - 10TL (closed until December 2013) * Galata Mevlevi House Museum - 12TL * Yıldız Palace Museum - 8TL * Museum for the History of Science and Technology in Islam - 5TL
More details about the Museum Pass can be found on the website below.
The photo above is of Chora Church in Edirnekapı, Istanbul.