[Others]expiration date

When I stop my instance, it says:
The expiration date will not change after the Subscription instance is stopped.
What does this mean? I use pay_as_you_go. When does billing stop or start, as you go?!

If you using the  $300 New User Free Credit/coupon, it is valid for 60 days from activation date irregardless ECS instance state. In other words, the credit would be expired after 60 days validity.

Btw, there might still be charges (e.g. for provisioned resource e.g. disk space etc) even ECS is stopped.

It means that the instance you created is a subscription-based instance and not a pay-as-you-go instance.
so a subscription-based instance will only be terminated after the end date mentioned there. and you will be charged accordingly.
to avoid such situations please make sure you select pay as you go, model, when you are at the evaluation stage.

 Any other confusion please create a ticket to support team to get more help.

In PayAsYouGo an instance needs to be released, not just stopped. I  didn't understand that and maybe I still
don't.
If I release my instance can I create it again as it was? Isn't everything lost?