Why am I being charged for Heroku Scheduler?
You have provisioned the free Heroku Scheduler but are seeing charges for it on your invoice.
These charges stem from scheduler dyno usage. The Heroku Scheduler add-on is $0/month — however, it's an add-on that is used to spin up a dyno, and 1X dynos are $0.05/hour. In the add-on page, you can find this information under "Dyno-hour costs" in the Documentation.
To stop further charges, you can use Heroku Dashboard to either switch your app to Free Dynos or delete the Scheduler add-on altogether.