Hi Sam!

Thank you for contacting Microsoft Advertising with your inquiry. 

I see that you have a question about redeeming your $100 dollar credit while using the payment method PayPal. I will gladly be able to assist you with this matter.

In order to redeem a credit or promotional offer the only main restriction we have is that you must have a primary payment method on the associated account. Therefor, yes you will be able to have PayPal as your payment method and will be able to redeem your $100 dollar credit. The first blue hyper link below to review has all the restrictions for redeeming a coupon or credit. The last hyper link below is to show you how to add PayPal as a payment method.

Credit/Coupon Code Restrictions 

Pay with PayPal

Also referencing to your other inquiry about if there is a review process for adding a payment method. I will be more then happy to go over that with you.

All payment methods when applied to the account are review by the system. Unfortunately, I can't give you any specific details referencing to the payment method review process for security reasons. 

Lastly, to my understanding you are asking if you can add your virtual VCC prepaid card as your payment method. Although at this time, prepaid cards (from American Express, Discover Network, MasterCard, and VISA) can only be used to fund prepay accounts.  As long as the virtual prepaid card works like a physical one, and you can input the information the same, it should be accepted on our platform. You can reference the blue hyper link below to see exactly what payment methods are excepted with your region and currency. 

For more information on payment methods for your region please reference this article. Payment Methods

If you have any additional questions at all please let me know I would be more then happy to help. 

Thank you,

Diamond .G | Microsoft Advertising Support | 1-800-518-5689