For the first sales you should probably only sell to reputable members.
You send first and wait for payment after they get the goods, or use escrow.
When in doubt if someone might be respectable enough for you to send first(in case you don't use escrow), don't be afraid to ask.
I don't see a problem on you listing all you have for sale when you start, as long as you do what I advised.
Be aware that if you refuse to do any of the above people will give you a hard time.
Even if you do as I advise people will probably give you a hard time anyway, it's up to you to act professional, or not.
PS: This is my personal opinion/advice, don't mind the Moderator title written below my nickname.