Ask HN: (O/S) DevOps Tool to Identify Wasteful Cloud Spending

Hello, I am looking for a software tool that basically helps you lowering your cloud bill finding holes in the set-up or architecture.

I found Hana Insight (Azure) and Cloudability (AWS) with seems like the right tool but not Open Source and both have a lot of Enterprise features.

Does somebody know either an O/S tool or something that can support Azure & AWS?

It would be nice but doesn't have to be O/S rather have something that works :) Just curious if there are tools DevOps are using I am not aware of.