Is there any IKEA in Turkey?
Yes there are 5 IKEAs in Turkey, of which 2 are in Istanbul, and 1 in Ankara, Bursa and İzmir. If there are no IKEAS near your location, you can always order your goods online (www.ikea.com.tr), which will be delivered to you in exchange of a small extra fee.
This said, buying furniture in Turkey should be the least of your worries, since the country is known for having an excellent furniture market. You will easily find around furniture shops with modern (or classical, depending on your taste) furnitures at very low cost and very good quality.