It's worth noting that while YouTube could always run ads in your video, it is very rare to see ads in these types of videos. Ads are usually shown by high-trafficked videos, entertainment content, etc.
It depends on the product category you're in, and as always YMMV.
YouTube will only show ads for videos that either use copyrighted content in some way (usually music) or are videos by a YouTube partner and they have a deal with Google to split ad revenue for the video.
It depends on the product category you're in, and as always YMMV.