The easiest way is to purchase a UK or US Apple gift card and then open up an account with the iTunes store in that country. There are several vendors on the Internet offering this service, you purchase the Gift Card on-line and they email you the 'code' from the back of the card, which is all you need to open an account.
When you enter the details, it will ask you for a credit card number - just leave that field blank and enter the Gift Card details and you're good to go.
Since some apps, like the Sky News app, are free downloading those will, of course, not decrease your 'credit' with the UK or US iTunes store.
Several Forum members have done this without any problems.
Tim
Scotland