[Too]

It's heavily dependent on your scope and how much you value your time.

I could spin up a postgres docker container locally, in shorter time than it took me to write this comment. On the other hand that wouldn't provide readonly replicas, standby-replicas, cross regional, point in time backups where i can just click on a date and the database will restore, access controls connected to my company directory. All that would take months to engineer properly myself and after that continuous monitoring and replacing of disks.

Maybe you don't need all this, maybe you do, it's all a part of your workload and effort equation. It's not possible to just take the cost of a VM and multiply with number of hours in a year.