Why does the post say a certain price but when the customer is sent to Amazon’s cart sometimes the price is different or higher?
Auto updated pricing – how to make sure prices on posts are up to date?
What is happening is the lowest new price is displayed and added to cart. Most of the 3rd party sellers have only one copy at that price so if someone adds it to their cart, on Amazon, then that copy at that price is not available any more. So Amazon puts the next lowest available copy in their cart.
To get hyper accurate Amazon pricing on your site you would need to set the Caching feature of WP Zon Builder to cache for 0 days. That way the price displayed on your site would be the most up to date price. Doing this it would be more likely that the price in the cart will match the price the Amazon store will stick in Amazon’s cart. If someone else buys the lowest priced item then Amazon would substitute the next lowest priced item. I don’t think this would occur very often but it could. Just keep that in mind.
The best chance of making your On-Site Cart be hyper accurate would be to employ the caching method I mentioned. Other wise just send them to the Amazon Product page and let them choose what price point they want to purchase at.