AFAIK, there are exchanges that do it through community votes. I don't know what exchange in particular that still does it, DYOR.
Many, even Binance still do (most recently around last June).
The best solution to listing coins for free is by community votes. In the past, I have come across several projects that are listed on the market quite well known for their community support and having a sizeable trading volume that has caught the eye of the exchange itself. And that will happen if your project has been listed on other exchanges before.