Many VPN's offer a 3 day trial or something like that. If you are looking for a 100% free VPN . . . I would strongly recommend that you look for a paid VPN . . . the free VPN's are not worth the money you spend on them LOL
Here is a great place to start when considering a VPN:
The most important things (which are not mentioned in that article) are:
1) Can you port forward with the VPN???
2) Get a VPN based in a country which is different than your own country.
3) Get a VPN based in a country which does not have strong political ties to your country (for example if you live in Canada do not get a VPN based in the US).
4) Use a VPN server that is based in a country which does not have have strong political ties to your country.
I know some of those sound the same so let me give you an example.
Say you choose VPN-A.
VPN-A is based in South Korea but they have servers in:
So even though you live in the US you are not complete safe with that South Korean VPN if you use the servers in the US and or Canada because even though South Korean laws would protect you from the anti-file sharing folks . . . the local laws apply to their servers in other countries so even using a South Korean based VPN is not enough you want to use one of the servers in Romania, Sweden, or South Korea for the most protection.
The downside to using a distant server is that your speed will suffer a little . . . but if you are looking for protection you are probabaly willing to sacrafic a little speed (by a little speed I mean somewhere in the 2% to 8% range).