Amazon has released product targeting for Sponsored Display ads, allowing merchants to target similar or complementary products and categories via Seller Central
Amazon says that, with these options, you could possibly running shoe ads (as an example) to appear on category pages for running shorts.
Similarly, you can cross-promote your own products. “If you also sell socks, product targeting placements on your shoes’ product detail page makes it easy for shoppers to add a pair of socks to their car with just a few clicks.”
On Amazon, Sponsored Display ads will appear next to reviews, on search results pages, as well as the right rail on product detail pages. The ads auto-generate, as well as feature a product image as well as ratings, deals and savings badges when applicable.