Network File Search

My users need to be able to search our archive server, but using Window Search is very hit and miss.  This may be partially because the file paths can get quite long.  Shortening the file paths is not an option.  I want to install some kind of search service that will index certain network shares to facilitate user searches.  I've looked into Microsoft Search Server 2008 Express, but the few bits of information on setting it up seemed vague and involved.  There is no funding for this and the chance of getting funding for this is remote.  What free or cheap alternatives to Microsoft Search Server 2008 Express are out there?  What is the easiest to setup?