You might want to read all the posting in the "mucuna puriens" thread posted below.
A good informative site on mucuna is:
http://www.parkinson.org/Page.aspx?&pid=459&srcid=379

Mucuna is cheapter than Sinemet, that's not why I take it but it doesn't hurt. I believe it's overall better for me.
Enjoy life.
Max

PS Taking mucuna is only a small part in improving pd symptons.