If you would rather use credits option like in iTunes, then you can do the same in Google Play store from today (available only for the US users for now). Click the "Buy Google Play Credit" at the bottom of the Google Play store page (as shown above). Once you click the Buy link, you can add different amounts as shown in the picture below.
After the purchase, the amount is added to your Google Wallet and you can access it in "Google Play Balance" to pay for your purchases in Google Play (Apps, Music, Books, Magazines, Videos and Devices).
This will be a good option to have if you don't want to pay with credit or debit cards in Google Play, just add the amount to your Google Play credit one time accessing your card.
If Google adds the Gift option for this it will be good.
