It is possible to purchase additional IP addresses for a virtual private server, however you must have reasonable justification for the use of the additional IP address due to limited IPv4 space available globally. There are only two justifiable reasons for requiring a dedicated IP address:
 

1. Installing an SSL certificate. If you have a domain that requires an SSL certificate on your virtual server, then you must send us your proof of purchase of the SSL certificate for the given domain before we can issue your dedicated IP address
2. DNS Name Servers. If you are setting up your own name servers, then you will need a dedicated IP for each (two maximum). You must prove that your name servers will be registered within 30 days of issuance of the IP address otherwise the IP address will be revoked.

If you are on a shared server an SSL certificate is not justification for a dedicated IP address allows the use of a single IP for multiple certificates.