You can buy credit for usage on Azure through Open Licensing. This includes Open, OV, and OVS, as well as educational and government schemes.
How Does It Work?
The process is:
A customer asks to buy X amount of credit from a reseller – the next bit of stuff is normal licensing operations that the customer does not see.The reseller orders if from a distributor.The distributor orders the credit from Microsoft.A notification email is sent out to the customer with a notification to download an OSA (online services activation) key from their VLSC account (used to manage their Open volume licensing). The customer is back in the process at this point.The customer/partner enters the OSA key in the Azure Account Portal.The customer/partner configures Azure administrator accounts and credit alerts.
Credit is purchased in blocks of $100. I believe that it is blocks of €75 in the Euro zone. So a customer can request $5000 in credit. They don’t get 50 OSA keys: they get one OSA key with a value of $5000.