Adaraba, There are those who are machmir and don’t sell chometz (they get rid of it all) and don’t eat any chometz that was sold by others after Pesach.
there are those who only sell items that would be a big loss to throw away.
There are those who sell closed packages only.
There are those who won’t sell actual chometz, but will sell not-kosher-for-Pesach things that don’t have actual chometz in them.
There are so many different approaches, which is why that now that you have a basic understanding of what the issue is, you can ask your LOR.