There may be many reasons why you want to use a VPN, just bypass your local school internet filtering, the Great firewall of China of the blocking of Hulu and other online TV websites to non US IPs, whatever your choice, you have now available some free VPN to do that.
Some of the free VPNs, like Anchorfree, are financed through advertisement, this means you will have to view a small banner while surfing the internet, but other than this it works fine.
Other of the free VPN have time, bandwidth and data download restrictions, and most of them, if not all, will not allow you to use Bit torrent through the VPN, you will need a paid solution for this.
List of free VPN for anonymous internet surfing
No logs premium VPN
If you need a reliable premium no logs VPN provider that will get around internet filters and provide you with secure and anonymous internet browsing, try VPN4All or Hide My Ass.