If you need protection, the official 360 Total Security website provides several safe alternatives:

Before you hunt for a serial number, consider that that is often sufficient for the average user's entertainment needs.

As a "Total Security" solution, it maintains several pillar features available across most 10.x versions: Download Free Antivirus | 360 Total Security

Qihoo 360 frequently offers discounts or "refer-a-friend" programs that grant Premium days for free.