App store - buying with paypal trough iPhone

Question is simple, how to use paypal as payment method? I don't know is this important, but I am no-U.S. citizen.

I suppose this is possible, just look at the link: http://ift.tt/1yRWJAn but there is no details about how to use it. I know there is paypal app, so if anybody have experience with that app, can answer too.

Mainly I would like to buy apps from the appstore via paypal. My debit card is connected with my paypal account. I know I can use debit/ credit card information to buy, but that defeats whole purpose of having an paypal account. I guess this can be easily done, but I just can't find paypal option on my iPhone's app store app...