We did this at OpsLevel a few years back. Went from AWS managed NAT gateway to fck-nat (Option 1 in the article).

It’s a (small) moving part we now have to maintain. But it’s very much worth the massive cost savings in NATGateway-Bytes.

A big part of OpsLevel is we receive all kinds of event and payload data from prod systems, so as we grew, so did our network costs. fck-nat turned that growing variable cost into an adorably small fixed one.