Fck-nat is great, and I'm running it for the exact same reason that the NAT Gateway is expensive for my hobby project. I configured it with an auto scaling group to bring it back up if the instance dies. The instance doubles as a bastion host as well.

Awesome, will look at deploying fck-nat.dev. Love the name. So absurd AWS hasn’t updated their NAT instance AMI since 2018 and running Amazon Linux v1 which is end of life.