If you generate a post that says "Amazon Price: N/A" see if the Amazon product is available as new, or only as used? That could be the issue.
if you can clearly see a price for a new product on Amazon, please send us the direct link to a post that has this issue and we'll take a look.
Also, please send us your WordPress site's login URL, username and password, in the following format:
Article ID: 154
Category: Associate Goliath Wordpress Plugin