The Azure Marketplace is your online store for software applications, developer services and data, all pre-configured for Microsoft Azure. In order to access some of these services a credit card is required to be configured within the Azure portal.
BizSpark members have a luxury of free Azure credits but at times their compute charges may exceed the limits of what their plan is. A credit card is required as well.
Here is a quick video of how to add a payment method to your subscription.
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