It being the newest smartphone out there, you may need to wait for a wide variety of covers coking up in the market. A few I could find are -
1. SNE Exclusive high quality flip case cover For OBI WORLDPHONE SF1
The cover is available in purple color. You can buy it on EBay India. The cover haw been priced at Rs. 249.
2. Sne Flip Cover For Obi World phone Sf1
The cover that has been explained in the above response is available on SnapDeal at Rs. 349. But the item is out of stock right now.
It appears it is the only cover currently available for the device. It can be found with different sellers with a slightly differing price tag.