Don't bother with trade chat, nobody with that kind of cash uses it, since it's all scammers and bots nowadays and not worth sorting through for a decent deal.

Using premium tabs is easy, just right-click on the tab and set it to public, individually priced. Then right-click on the bow and put "~b/o 30 ex" in the note. I think there's another option to set the price with a drop down, idk I'm playing SSF this ladder and don't remember.