Just my anecdote, but when I used Instagram (stopped probably 2 years ago), the ad targeting was pretty terrible for me. Occasionally they would get something completely on the nose (to the point that it was a little creepy), but most of the time (>90% probably), the ads were completely irrelevant to me, either for things I already have and have no need to replace, or for things I don't think I'd ever conceivably buy.