If your current email marketing billing plan is of the Monthly Plan variety, then you are entitled to an unlimited amount of emails to be dispatched each month, so setting up automated events won't have any effect on your credits.
If you have purchased a Credit Plan, credits are deducted as usual, according to the number of emails that are sent following the triggered events. So keep that in mind when you set up an automation workflow.
In case you have any additional questions, make sure to learn more about our platform's pricing policy as well as our Pricing Options.