According to a Google Blog Post:
“Starting on October 17, Google Shopping results in the US will come only from merchants who are Product Listing Ads advertisers.”
What does this mean for eCommerce shop owners? If you’re currently using the Google Product Search feed, you will no longer be able to use the feed unless you agree to pay Google for each click your potential customers will make.
If your website is good at converting traffic, this may end up helping your site as it will thin out the competition of the sites that can’t afford to pay for their clicks. This is why it’s very important to optimize your site to make it easier and more clear for the customer to order.