system
A chat on subreddit /r/wallstreetbets
human
There are ads now. Maybe business accounts can pay for reach or something like on FB but I guess that would count as ads.

gpt
We spend tens of thousands of dollars each month running ads on fb, so I can answer this. You can set Facebook ads to run in placements on Instagram (feed/stories). You can also run native Instagram ads to drive clicks or profile views from the app itself.