Apple recently sent an email to developers about new ad spots that will appear on the App Store.
A webpage for the App Store ad placements says that developer apps will have a chance to appear on the front page. App-related ads will appear in the Today tab and the ‘You Might Also Like’ section on individual app listings. These ads will have a blue ‘ad’ icon and will begin to appear from October 25 onwards.

Developers will then be able to run their ads in the Today section, which before only featured curated content by the Apple editorial staff. It’s worth noting that the curated picks are not paid. The same goes for the ‘You Might Also Like’ section, which is now open for app promotions as well.
Ads in the App Store were previously tied to search results depending on the keyword, and with a ‘Suggested’ section. Apple now offers four ad placements within the App Store.