I've seen quite a few forum posts of late asking something along the lines of "Why can't I create A series VM's any more" so I thought it worth a quick post to detail what's up and how to fix it.
The problem here is that if you use the Azure portal to create a VM and use the defaults provided, when you come to selecting a VM your presented with a Window like this:
Even when you go to "View All" your still only presented with DS, FS,GS series VM's, you can't find A, D, F, G or N series VMs. So what's going on?
The clue is in the fact that only the *S series are available. The portal has defaulted to selecting SSD based VM's that use premium storage, I suspect due to the general recommendation to use premium storage for production VM's to get things like single instance SLA's.
To get access to the non premium storage VM's you need to go back a step to the basics section and make sure you select HDD in the drop down for "VM Disk Type". Once you select this and move on to the Size screen you should then be able to select all the non S SKU's.
Note that to get the new GPU based N series VM's you also need to select HDD, as these' VM's don't contain SSD's.