The most common reasons to use a VPN are:

• Reduce the costs of telecommunications (especially long distance phone charges) by using the Internet to carry traffic
  
  
• Reduce telecommunications costs by minimizing the number of lines accessing a corporate site
  
  
• Save operating expenses by contracting VPN management and equipment costs to a service provider

Long distance charges can be reduced with a VPN because users are placing local calls to their ISPs instead of making long distance calls to the company.

The number of access lines and their costs are reduced because many companies pay monthly charges for both high-speed Internet access links and frame relay, ISDN Primary Rate Interface or T1 lines to carry data. If the VPN allows data traffic over the company's Internet access lines, the number of installed lines needed is reduced.

Operational costs are additionally reduced by outsourcing remote access to an ISP or other type of service provider because by giving users access to the network via a VPN, modem pools and remote access servers can be eliminated. The operational cost savings come from not having to manage those devices.