Best Free Data Recovery Tools

Need to recover my files. I did a system recovery and lost all my files.?
what are the best data recovery tools?
I would like free ones that really work
or ones that you have to pay for that really works. I need my music files also
good luck !! , why didn’t you back up your files first ? , u may be able to use a software recovery disk , but i would be willing to bet that the mp3′s are gone