First or all, the SQL Server Setup media is agnostic to where you are. It will be the same as on on-prem.
Have you looked at https://learn.microsoft.com/en-us/azure/azure-sql/virtual-machines/windows/frequently-asked-questions-faq?view=azuresql? As I understand it, you should select Pay-as-you-go to avoid extra costs. But read it yourself and make your own judgement.
There is another important thing to observe: While you can install multiple instances on Azure VM, you can only manage the default instance through the portal. (This is also discussed in the topic above.)