From mid October you can list your products in the Google Shopping tab for free.
‘Today we announced that we’re bringing free listings to the Shopping tab in countries across Europe, Asia, and Latin America. Just as we don’t charge sites to be part of the Google Search index, listings for participating retailers are eligible to appear in these results at no cost to them. Paid listings will continue to appear in ad slots and will operate in the same way as Shopping ads do today.’
I’m glad they’ve made this change. This used to be the norm for the product feed until they made it ad supported only.