Understanding cloud costs is an area Infracost (YC 2021) is working on. Give it a Terraform script and it will calculate the dollar cost; it can also diff costs in a CI pipeline: https://www.infracost.io/
As with all cost estimation tools, the projection is only as accurate as my usage projection -- but a nifty CLI and/or CI integration sure beats having to deal with AWS price sheets!
Love the site and the upfront screenshots.