Very new to Githib and currently using the "free" version. At this level what, if any, audit logging is available? Can I find out who accessed a repository and if they had download any files? If not, at what subscription level would this type of logging become available to me?
There isn't any audit logging available to GitHub users that allows for tracking of what files have been downloaded (unless you're talking about releases) and by whom. The closest you could come to what you're asking for is viewing the traffic information on a repo or getting download counts for releases. All of these stats are anonymized for GitHub user's privacy.
I hope that helps!