The amount of time depends on the payment system and how fast they are to come back to us saying it's complete. These types of system where you pay with cash take longer, but rest assured, once they notify our system of the payment you will get the Moolah right away, delivered to your gift box ingame.
You can always go back to the payment screen and click My Account, Where's My Moolah and fill in the form to request information on your payment directly from the payment provider.