My guess is, Amazon is buying this data from Google. When you go to Amazon to do a search, regardless of whether you are logged in or not, Amazon is recording your IP address and what you searched for.
If you do not make the purchase, Amazon knows this. Amazon then pays Google a fee for to push ads to your IP address with exactly the same product that you searched for on Amazon.
If you asked Google to not provide your data, they would laugh in your face.
The only realy way to stop this would be to find some sort of IP translation program that would hide your real IP address from Amazon. Wait until Google buys Amazon. :)