Hello,
My name is Wiktor Koźmiński and I will be glad to take this task. This is my first offer on freelancer so I provide very attractive price.
I have made rich snippets literally 5 days ago for my wife - she have online store on Prestashop (by the way made by me also). You can see one example at:
[login to view URL]
Also I can provide you open graph in code.
Best wishes,
Wiktor Koźmiński