How can i spend $15 cent on the App Store? It's impossible. I want to change my country

Try contacting iTunes Support and ask them if they can remove the balance from your account : http://www.apple.com/support/itunes/ww

1) Buy something and charge the rest to a credit card.

or

2) Ask Apple to keep the balance.

iTunes Customer Service Contact - http://www.apple.com/support/itunes/contact.html