Sure, but we're addressing people who are so far on the other end of the spectrum they're using a "serverless" database where they pay for the number of rows scanned per query. I think a managed DB is a better middle-ground for their capability level while still delivering massive cost-savings.

Amazon RDS lowest-tier runs about $13/mo for 10GB storage, 2 vCPUs and 1GB memory with automated backups and push-button restoring. And that would have likely met all of their needs with capacity to spare.

The time spent setting it up and managing it and then having to deal with backups/environment clones/access control/scaling limitations/etc. outweighs the savings for almost any company paying US wages. Especially since you'd need metal for everything and not just the db due to network latency.

They clearly don't have the skills for that. And at one insert every 3s, a managed service like RDS won't really cost much.