Yes, you are allowed to leave airport during layover as long as you will have a valid visa obtained.
Can I get visa online ?
It is very simple process for certain country passport holders including US and Canada to get their e-visa in few clicks online; In order to see requirements and get it online, you can visit official website of Turkish Republic https://www.evisa.gov.tr/en/
What is the minimum layover duration to leave airport for the tour ?
Recommended minimum layover duration is 7 hours layover for international connected flight and 6 hours layover for domestic flights from Istanbul International Airport. We can accommodate business travelers with shorter layover duration.
How early should we back at the airport?
For international flights, if the luggages are checked through to final destination, and already have your boarding pass, you will be dropped off 2 hours prior to departing flight. For domestic flights, 1 hours is suffice.
Where should I keep my cabin luggage ?
You can use attended baggage storage or baggage storage lockers that are available 24 hours a day in Istanbul Airport.
Why are the prices different than shown in website ?
Tour prices are given per person and as the number of participants increase, the tour fee decreases, same as it goes up once there is only one participant.