You can also buy a turban -- really you are buying turban fabric - at local clothing shops in Indian neighborhoods. Let's assume you are not writing from India where the fabric centers are legendary. Nearly every major metropolis in Europe, North America, parts of Africa, the Far East (yes), the middle east (Yay) has a South Asian neighborhood. Just for the fun of walking around, shopping, and eating in the restaurants, everyone should treat themselves to the trip.:happy::happy::happy:Then go looking for turban fabric.
To buy the turban -- look for a ladies dress, kurti, salwar suit, sari shop. Go inside. Behind the counters you will most likely find fabrics for the personal tailoring of salwars and kurtis. In that same section the shop keeper will probably have turban fabric. If not, he will tell you where to find it.