I’ve made a list of the best free VPN trial I could find. Note that I’ve only included reliable VPN providers that I recommend.
Apparently, PureVPN and VyprVPN offer free trials, but make it difficult to get your money back, so you may want to avoid those services.
IPVanish offers a seven days money back guarantee. They state that if you don’t like the service, you’ll get a full refund. Good support for P2P/Torrenting. Servers in 44 countries.