Sponsored Products vs Sponsored Brands: Which Fits a Single-Book Author

Short answer: Sponsored Products, almost always. Sponsored Brands is designed to showcase a catalog of several products under one brand, which doesn't make sense when you only have one title published.

What each one is

• Sponsored Products: promotes an individual book in search results and product listings.
• Sponsored Brands: shows a banner with a logo and several products from the same brand — built for catalogs with multiple titles.

When Sponsored Brands starts making sense

Once you have 3 or more published books (say, a series), Sponsored Brands can help showcase the full catalog at once, instead of advertising each title separately.