I am getting notice while adding my debit card that your payment method was declined app store. I used my Debit card because it has zero balance to add purpose only. But app store is saying that payment is declined. So it means Apple will charge without asking me? How much will Apple charge and Will that amount be refunded or not, if refunded after what time?
Companies can reserve an amount of money on a credit or debit card without actually charging it, to ensure that you can charge the card later when they need to. This is called an Authorization request to your credit card.
I expect that Apple are reserving a small amount of money when you register a card, and then releasing the reservation immediately, to make sure that the card is valid.
That might reduce your available credit by a small amount for a few days, if your card provider has bad IT systems, but it won't actually charge your account.
This is a standard practice that many companies explain in either their FAQS or T&C's.
From the BBCshop faq.
I have been charged for my order but it hasn't been despatched
Please be assured that here at the BBC Online Shop we do not charge your credit or debit card until your order has been despatched from our warehouse.
We send what is called an authorization request to your credit card company. Your credit card company verifies that the card is valid and that the amount of your transaction is available. If the card number is valid and the funds are available, they put an authorization hold on the funds. An authorization is only a hold on the funds for a possible future transfer. This hold is temporary, and if the transaction isn't settled it will expire without any action. It is not a completed transaction and no funds are transferred at that time.
Your credit card company may still show a temporary authorization hold on the funds after your transaction is completed. It can take several working days for them to process the void on the authorization. The time will vary from one company to the next. Unfortunately, many customer service people at the card companies don't understand the difference between a settled transaction and an authorization hold. They will tell you that it was a valid transaction.
Are there any differences in paying with a credit card versus a debit card?
The main difference is that most credit card companies first authorize a customer's card when an order is placed, then actually charge the account when the item is provided -- in our case, at the time we ship your order. The only exception to this is digital purchases such as NOOK Books, NOOK Newspapers, NOOK Magazines, and NOOK Apps—for these items, the credit card account is charged immediately.
Most debit cards reserve funds from a customer's bank account at the time of the original transaction. That amount, therefore, is unavailable to you. When the order ships, the bank pays that debited amount to BN.com. For digital purchases such as NOOK Books, the order amount is immediately debited from the customer's bank account.