This seems like something you could build over a weekend. I'm excited to see an open source alternative for this.

EDIT: Folks, if you're truly large enough to benefit from vantage, please talk to your AWS/GCP/Azure rep and work with them on deciding what you should do for committed usage. There are a lot of ways to save money on cloud costs, and they all start with a conversation with your cloud provider. If you don't have enough spend to have a cloud provider rep, vantage isn't going to save you that much money.