Hello @chy ,
Thank you for your post! In regard to your inquiry on the $200 in free credits you have available on your subscription, it will still be available for the remaining month if you upgrade to Pay-As-You-Go from Free Trial before the end of the 30-day free trial period.
Please see the following below for more information:
What happens to my unused credit if I upgrade before the end of 30 days?
If you move to pay-as-you-go pricing before the end of 30 days, you won’t lose your credit. When you move to pay as you go, any credit you have remaining will still be available for the full 30 days from when you created your free account.
In addition, I wanted to clarify that you will not be charged anything if you are under the $200 USD limit and not until you have exceeded that limit would you be charged on your Pay-As-You-Go Plan per the following:
What happens once I use my $200 free credit or I’m at the end of 30 days?
We’ll notify you so you can decide if you want to move to pay-as-you-go pricing, enabling you to purchase Azure services beyond free amounts. If you do, you’ll keep getting access to all the free services. If you don’t, your account and services will be disabled. To resume usage, you'll need to move to pay as you go.What does it mean to upgrade my account to pay as you go?
When you sign up for an Azure free account, you get $200 credit. In the first 30 days, any services you use beyond their free amounts will be deducted from that $200 credit. When you've used up your $200 credit or 30 days have passed (whichever happens first), you'll need to upgrade by moving to pay-as-you-go pricing. That way, you can keep getting free amounts of services and purchase services beyond their free amounts as needed. The cost of those services is charged to the payment method you provide.
I hope this helps answer your questions and I am linking the FAQ's from above here for more information on Azure Free Account FAQ and am happy to help should you have any further questions or concerns. You can also contact sales to learn more.
Thanks!
Carlos V.