You CAN use a non-US credit card on Apple Store (US) Online (www.apple.com/store), they will take it just fine
On the other hand, you cannot use a non-US credit card on iTunes Store (US)
So, yes, I see where you are trying to go.
You can purchase iTunes Gift Card on Apple Store Online (US) and have your friends in the US send you those. You can then use the Gift Card balance to purchase on the US iTunes Store.
The New Flying MacBook Pro; Seatbelts sold Separately!