I investigated EBS snapshot as an option, but there were two problems. 1) cost as i mentioned initially - for just AOSP source tree alone you are looking at > 250GB and at a cost of $0.05 per GB you are already at > $10/month and 2) EBS snapshots lazy load from S3 which gives TERRIBLE performance which means you end up with far far slower builds. AWS released a feature "EBS Fast Snapshot Restore" to workaround this issue, but it's extremely expensive.
That's likely the size of the entire checked out tree, which would include all of the files.
I just ran the command here and my AOSP 11.0 checkout is 54GB, minus any git history, since I clone from a local mirror and use '--reference' to avoid having to copy objects.
A lot of the size here is from the various prebuilts, AOSP build is quite self-contained (jdk, clang, etc) and barely uses anything from the host.
