how do i register a business name? how much does that cost?
Mine cost me $90, plus $3 for laminating the certificate and another $5 for the xtract of particulars to prove I own the name, for opening a business bank account with. (that is in WA)
Look it up on the net, if you google business name registration {in your state} you should get something. In WA it is the Department of Consumer and Employment Protection.


around how much does it cost for domain names?
From memory, mine was about $15 a year...

How much does it cost to get a abn and how do i go about doing this?
ABN is FREE - go to the ATO site and follow some links


is there any particular order i should be doing this is is there anything else i shoudl be thinking off?
MUST have reg business name before you open, MUST have ABN before you begin trading....most places for wholesale require a ABN as proof for a wholesale account.
Need t think about GST reg - if you arent going to be turning over a lot of money, then probably not worth it - but check out the ATO website or give them a call.
Are you a food based business? they require a whole heap of other requirments and registartions.

HTH=
Other than that - good luck!!