Price $3.95 / 10 GB is for per website or per VPS?

It is per Domain per Month. Rather than the "per domain" term, the ideal term should be "per URL". This URL can be used for unlimited number of domains. For example, you sign up for a CDN Plan for the Source URL as http://source.yourdomainname.com and CDN URL as http://cdn.yourdomainname.com.

• 1st URL: http://source.yourdomainname.com ==> This is a source URL. All static original content (images, css, etc.) will be published here.
• We will setup the 2nd URL: http://cdn.yourdomainname.com ==> Any content that is published in the source URL is distributed over CDN using the 2nd URL.
  
  

You can use this CDN URL for any number of domain name.

Looking to integrate your website with CDN? Please refer to the Integrate website with CDN for more details. 

Looking to enable CDN Resources for SSL Enabled Website? Please click on Enable CDN Resource for SSL Website for more details.