Living Water Op Shop is the best op shop I've found. It's pretty big and open four days a week. You can easily spend at least half an hour rummaging through racks and racks of clothes. There is also plenty of kitchen stuff, magazines, curtains - whatever you want! Their prices are terrific. You never know just what you will find!
They often run specials on clothes, mostly for just $1.00. It can get quite busy during those times, so come early.