There are plenty of free anonymous proxies on the Net. However, it would be a mistake to rely on any of these for any level of security or privacy.

The reason is that it's usually impossible to know if a given free proxy is trustworthy or not. Many free proxies are set up by spammers, phishers, and even surveillance agencies, to try to steal user login data or profile your actions as you surf through the proxy. In addition, many free proxies, while not run by malicious operators, may not be very secure, which can again lead to your potentially very sensitive data falling into the wrong hands.

A well-reputed commercial service, on the other hand, has a commitment and contractual obligation to customer privacy, and a reputation to protect.

Free proxies are also favored for abuse by net criminals, which leads to them being quickly banned from many sites. A commercial service, in contrast, works hard to keep miscreants away, and protect its network from abuse. Other areas where free proxies can be far less than optimal are speed and reliability of service.