Google collects the purchases you've made, including from other stores and sites such as Amazon, and saves them on a page called Purchases.
Apparently https://myaccount.google.com/purchases is a reasonable place one could start for creating acquisition posts on their website. The downside is the realization that Google is tracking all of this without making it more obvious.
Chris, this is why I think that Google’s talk about wiping things such as our search records is something of a ruse. What does it matter if they have the raw data anymore (emails, searches etc) if they have already stripped out the core information and stored it somewhere else?