Originally Posted by ISTFlyer

1- It's open 7/24

2- Yes, there are lockers in the lounge; however, after your arrival to IST, you might need to reclear security to access the lounge and put your belongings into a locker.

3- It's a nice tour, but you could see much more during that period if you travel by your own.

4- Answered your question in the respective thread. Also, a suggestion to you would be to read the WIKI of that thread. Non-TK*G's traveling in Economy is not eligible for sleeping rooms at all.

5- If you're taking the tour, ₺100 would be enough. If you're going to sightseen by yourself ₺300 ( if you prefer to travel by bus ), ₺600 ( if you prefer to travel by taxi ).

6- Arriving at the airport at 19:30 would be fine as you would have fast-track access at both security and passport checkpoints. WCS, a taxi would cost around ₺125-200 depending on where you want to visit within the city center and the traffic at that moment. Uber works in Turkey but you could only order a yellow cab; no UberX, UberXL, UberBlack, etc... in Turkey