Here is a list of a few flipcovers available with leading E-commesrce sites for your Lumia 640-
1. Rkmobiles Flip Cover for Microsoft Lumia 640
This flipcover is available in Black color version. It was available till a few days ago on Flipkart at Rs. 165. You may need to wait till it made available again or check for it on other online stores.
2. D.rD Artificial Leather Mobile Flip Cover For LUMIA 640
You can buy this flipcover from Amazon India. It is available in sky blue color and is priced at Rs. 299.
3. DMG Premium PU Leather Flip Cover Case for Microsoft Lumia 640
This is an excellent deal for the Lumia 640. The flipcover is available in black color variant. You can get it from Amazon India at Rs. 449. You also get a matte finish screen guard and a stylus complimentary along with this flipcover.
4. Encase Synthetic Flip Cover For Microsoft Lumia 640
Available in black color, you can buy this cover from SnapDeal. It is priced at Rs. 425.
5. Luxury Look flipcover for Lumia 640
This cover again is available only in black. Made of artificial leather on the front and plastic back, you can get it on EBay India at Rs. 255.