The problem with changing the prefix is that it requires unlimited title editing… which we removed because as some of you will remember, people were posting a thread then deleting the whole title to make it just a period like this: “.” or to “DELETE ME” and other crap. It was abused quite a bit.
You do still have some time to change the title after you make the post in case you made a mistake, but things have been working fine without unlimited editing. Members have been PMing us or the mods have been closing threads as they see the OP post that the item is sold. We don’t even mind if you click the “report post” button to request a title or prefix change.
Now it might be possible that the form system we’ll use to solve the locations, etc. issues may have it’s own prefixes and edit settings. In that case you’ll have unlimited access to form editing and the prefix as well. But we’re still looking and testing classifieds forms / systems.