All STUFF needs to be bought directly from other players. Best places to do this are:
http://www.swc-gm.com
#swc-traders on irc.redbat.org
Keep in mind that you will need money for your STUFF purchasing needs, so you may need to join a faction and get some salary before you can buy anything neat.
It's advised not to blow all your money on stocks since they're not really worth much. :P