I believe that depends on the team and the exchange itself.
If the team plan to listed the coin/token into a non well known exchange that could be fast.
But on a well known exchange that could takes more time to get listed.
yes, most exchanges charge for that and it's not cheap. A good thing about stellar is their own exchange, no one needs to wait, I wish we could trade eth tokens like that. There are some dex for eth but the network fees and the minimum trade values are higher.