I am going over some product pages for an e-commerce site. My question is, within the product page, we have really good descriptions in the site content. I was thinking about copying all those good description and placing them as my meta tags. Is this a goood idea? Is it considered duplicate content?
Your meta description should be summary of your page content. If your can't create proper meta description, please omit it.
They won't be considered "duplicate content" - they'll just most likely be ignored as Google searches for a more relevant and accurate description of the page to show its users.