Everything I've had success on Mac with has required a cost like that and my employer has always paid, so I didn't need to look for a no-cost option, which seems hard to find for Mac.
I do know there are some open-source Linux-based file recovery utilities that I've used successfully on Windows and Linux drives, but I don't know if any of them handle HFS+ Mac formatted drives.
Oh, another couple of pay-for products I used a very long time ago were:
-and-
Can't remember why I quit using either of those, but I think they might be priced similar to the other pay-for options.
You might check all of them to see if any of them have demo modes that will allow you to recover a limited number of files to demonstrate their worth (but I suspect that their demo modes would simply tell you how many files they think they could recover if you paid them).
(edited 2014-05-11 16:06 gmt- corrected formatting)