Looking for a SaaS task scheduler

I am looking for a cloud-based SaaS task scheduler. One that I can access via an API to create scheduled jobs, perhaps by specifying a cron expression or similar. The task scheduler would only need to call an http endpoint at the scheduled time.

Does such a thing exist? I see Azure has it (Azure Scheduler), but the pricing seems pretty high: c. $0.04 per scheduled job, which would rack up costs if we are looking at tens of thousands of jobs...

Cheers SO!