Differences Between PPC channels like Google Shopping and Marketplaces like Amazon

What is the major difference between PPC channels like Google Shopping and Marketplaces like Amazon?

Google Shopping is a Pay Per Click marketing channel, where the products that show are based on both bid and feed optimization. When a customer clicks on a Google Shopping ad, they get taken back to the merchant’s website, where the purchase takes place. The only marketing cost, is the marketing cost per click.

Marketplaces like Amazon do not charge per click they charge a flat percentage commission on the sale (typically around 15%). The transaction takes place on the marketplace. On a separate note, Amazon also has Amazon Marketing Services, which allows you to bid on particular keywords to promote your products.