Compute
AWS Compute Optimizer
- Timebilled
- Bytesnot billed
- Callsnot billed
In one line
Recommendations are free; only the optional enhanced infrastructure metrics bill, per resource per hour.
What gets missed
Free until someone flips on enhanced infrastructure metrics, which then bills per resource-hour - and for Auto Scaling groups it charges per running EC2 instance, not per group.
Bills the same way
These services turn exactly the same meters, so what you learn here transfers.