There are no set rules written in stone and everyone should discuss and work out their own details when they meet before the l’chaim. Don’t cry and whine after you shake hands and then say “had I known they weren’t going to pay….” it doesn’t work like that. Lay everything on the table before you agree to the shidduch.
In addition, NO MATTER WHAT, keep the children out of the finances. NEVER, EVER send messages back and forth with the kids. Use phone, emails, texts if you have to but know that you have to communicate with your mechutanim on your own. If you experience issues ask your Rav to assist but keep the kids out of it.