There is a comic shop in Elizabeth Street, Brisbane called Comics Etc. Since the early 1990s, it has moved premises a few times, but has always been located in the Brisbane CBD. The shop has a secondary website called Comics Etc Direct. According to the site, they "order exactly what you want, saving on import charges and avoiding dead stock so you can save big".

Disclaimer: I don't buy comics, so I've never ordered from either of their websites.