If you want to take a rest between 2 flights, Istanbul Airport offers 25 sleeping pods called “iGA Sleepod”. This can be a good budget alternative if you want to relax in good conditions for one hour or two. Those sleeping pods are located at the International Departure Terminal close to gates C, D and E. Those pods are pretty well designed with a space for your hand luggage under the bed and a USB socket to charge your phone. And you won’t be bothered by the aiport light with the retractable roof of the sleeping pod.
This service costs 6 euros/hour between 7am and 7pm and 9 euros/hour between 7pm and 7am. An extra blanket or a pillow will cost you an additional 2 euros.
It is better to book a hotel if you plan to spend the whole night at/near the airport. But for a shorter time, you may want to consider that option.