You don’t have to spend a fortune to be successful with file analytics. You can take the “Yugo” approach when there are heavy constraints on costs.
There’s a lot you can do with free or nearly free file analytics tools. There are inexpensive applications such as TreeSize Professional, which look at wrapper metadata such as file type, name and path; extensions; and dates.
Even this inexpensive approach can help you tackle Redundant Obsolete and Transitory (ROT) data. Using simple power shell scripts you can act on that ROT—and, at least be a little further along than you were before.