Hourly FortiFlex on Azure for FMG

Hi,

I am looking at using a small FortiGate setup on Azure for lab practice.

I have found this to be relatively simple and looks like I can use the PAYG model to simply create a VM and use it.

What I am struggling with is FortiManager, all the guides indicate a BYOL licence is needed, but during the setup it gives the option for FortiFlex which looks to be the right idea but I have no idea if I can buy a small number of points anywhere or do PAYG…

Also this marketplace item exists and I am not sure if this is what I should be using as a way to pay all through Azure?

Fortinet FortiFlex Usage-based Licensing - Microsoft Azure

I can see this has a purchase option which then gives an option of 1,2,3 years but also it gives the create option which does create a VM?