I believe the system waits a while before collecting payment so that you aren't separately charged for purchases you've made close together. As far as I can remember I've received the invoice a few hours after making the purchase.
I don't know about itunes but, whenever I use my debit card, the money comes out immediatly
No. Technically, a prepaid MasterCard Gift Card is a debit card. iTunes does not let you connect debit cards to your account and use them to buy things.
Yes ,you can.
credit and debit
Cash, check, credit card, debit card, gift card.
No. You can use PayPal and any major credit/debit card, as well as an iTunes Gift Card.
Instantly
A Visa debit card machine allows one to take payments from Visa credit cards. They are used by businesses to receive payments from customers electronically.
iTunes cards or debit/credit card if that is what you mean
If you mean purchasing songs from iTunes on an iPod, Yes. On an iPod touch you may download music from either a credit/debit card or an iTunes gift card.
You can create an iTunes account without inputting card details. That's why they sell iTunes cards.
debit card the card holder uses the balance of his or her own account in bank and make immediate payments while purchasing. smart card it can be used as a cash where accepted