Lightsail Usage Billing

As an existing Lightsail customer using the basic Linux/Unix solution, you'll be pleased to know that Lightsail offers flexible billing based on actual usage. If you decide to only spin up a server for a few minutes instead of the whole month, you won't be billed the full $5 monthly fee.

Lightsail plans are charged on an hourly, on-demand basis. This means you only pay for the time your instance is actually running. If you create an instance, use it for a short period, and then delete it, you'll only be charged for the hours it was active.

For example, if you use the least expensive Lightsail instance plan (which is the $5/month plan) for just 100 hours in a month, you would be charged approximately 46 cents (100 * $0.0046 per hour). This prorated cost is based on the total number of hours you used your Lightsail instance for that month.

It's important to note that Lightsail instances incur charges until they are deleted, not just stopped. So make sure to delete the instance when you're done using it to avoid unnecessary charges.

This billing model allows you to be cost-effective by spinning up servers only when needed and deleting them when they're not in use, without having to commit to a full month's usage.
Sources
Billing and account management - Amazon Lightsail
Instances - Amazon Lightsail