Indeed, for small apps that average 2 instances or less during the month it's now cheaper to run App Engine Flex than GKE. Each instance costs about US$ 50/month in US central.
For those that are not aware, App Engine Flex runs services based on Docker containers with autoscaling similarly to Kubernetes. It has way less features than GKE, but if you are just running a standard app that only needs to connect to a database that is more than enough.
Bonus points: you can have multiple services, like back-end and front-end and make them available in the same subdomain - to avoid CORS problems. You can also host your front-end for almost nothing with App Engine Standard. It has an awesome CDN built-in if you know how to use it.
For those that are not aware, App Engine Flex runs services based on Docker containers with autoscaling similarly to Kubernetes. It has way less features than GKE, but if you are just running a standard app that only needs to connect to a database that is more than enough.
Bonus points: you can have multiple services, like back-end and front-end and make them available in the same subdomain - to avoid CORS problems. You can also host your front-end for almost nothing with App Engine Standard. It has an awesome CDN built-in if you know how to use it.