If you live outside of the US, its likely that you are paying more for purchases on iTunes , as apple tends to increase prices for non-US customers. There are also some apps (like Sling TV) which you may want to use which can only be accessed on the US store.
You can get around this quite simply by creating a US iTunes account using the link below.
http://www.lifehacker.com.au/2010/09/how-to-set-up-a-us-itunes-account/
A US iTunes account can also be used for paying for service such as Hulu, by linking your Hulu subscription to your new US iTunes account.
If you need to add credit to your new US iTunes account, and you do not have a US address or credit card, you will need to use a virtual credit card like USunlocked . You will need to go through a few of the normal ID checks to sign up for this , but once you have it, you will unlock the door to not only US iTunes purchases (which are likely to save you money on music, apps etc), but it also enables you to shop for bargains online at US stores like Amazon.