GR of Free goods/Donated goods

Hi Experts ,

Please advise me what is the right way to perform GR for donated materials/Free products .To my knowledge we can receive free products or donated products by MB1C or MIGO using movt. 511 (Please correct me if i am wrong) .

I would like to know how should the PO be created (should it be created for zero value)..if PO is created for zero value how will the value of the material be posted to general ledger when GR is done.Your comments will be appreciated.

Regards

Albert