Are LightSail alarms separately chargeable?

HermesIV,

Thanks for choosing Lightsail!

We do not charge extra for alarms but there are limitations on how many you can create per resource. Here is a doc on that subject specifically for instances:
https://lightsail.aws.amazon.com/ls/docs/en_us/articles/amazon-lightsail-adding-instance-health-metric-alarms#instance-alarm-limits

I hope this helps!

Donley