VPN = 'virtual personal network". It hides your IP address (which identifies you to websites) so that they won't see where you're based.
Some VPNs might do nothing more than give you a 'fake' IP address (which could be anywhere in the world) but you clearly need one which allows you to specify that you require your internet traffic to be seen as derived from a US address.
You usually have to pay for VPN services but there are some free ones around. However you need to note that some of them come with hefty restrictions, such as forcing loads of ads onto you and/or slowing your internet traffic to a crawl. (In particular, I do NOT recommend HotSpot Shield. It made my netbook almost unusable and, even when I paid for the 'full' version, I couldn't get rid of the ads that are only meant to appear with the free one).
Go here, and then keep clicking 'Next', to read about those which might suit your needs best:
http://www.pcadvisor.co.uk/test-centre/internet/best-free-vpn-services-of-2016-in-uk-3613860/