Asking questions is a smart and quick way to learn what you need to know, no problem with that here!
You can offer snail mail packages to everyone and post in this thread. If you want to purchase one from a team member and then offer your own listing just to another team member, here is the thread for that:
https://www.etsy.com/teams/12997/snail-mailers/discuss/15700423/page/1Be sure to carefully read the rules in the original posting where Metzli explains how it works and how much to charge.
I hope this makes things more clear to you. I love your cards by the way, so I'm sure you'd create a fantastic snail mail package as well!