Hi!
Did you click to show all available sizes? which region are you trying to build in?
Usually Azure free credits for students enable you to use Azure B Virtual Machines type, You can try use 4 vCPUs or Less too.
how long do you have the subscription? you can use free account for 12 months, try to check the usage through the portal:
On the Azure portal -> Search for subscription in the search box at the top of the portal -> Select the subscription and You'll now see your usage for the free services
Some regions are also showing up as out of quota for some subscription types, try checking availability in other "less used" regions.
Get in touch if you need more help with this issue.
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