My friend paid around 950(incl service charge for filing the order) for this same cable for his asus laptop in a tier-1 city in North a few months back.
Do you have the laptop box? The cable is usually provided in the box.
2 years ago I too purchased a SATA SSD for my Asus laptop and was faced with the same issue. Thankfully I had retained the box and everything that came in the box was still there. SATA cable was one of them.