Schwarzkopf Essence ULTIME Diamond Color Shampoo 250ml $1.99 each (was $12.99). This is a supermarket dupe for a salon shampoo for coloured hair. I've seen this at the Warehouse for $10.50, but at this price it's good to stock up. It's quite a mild / gentle shampoo with a nice fragrance. They had 80 left at time of checking.
A much bigger Schwarzkopf range is also on clearance @ The Clearance Shed, I recommend you go there first if it's closer. RTC don't stock a lot of toiletries.
Thanks Avantime - definitely a lot more variety at the shed (including the biotin range) and still a bargain at $2.50 / bottle, especially if you don't want the ones for coloured hair :) Also noticed they had jars of the hydrating masques from that range for $3 each, although I haven't used them myself. Nice range at good prices.
In store, they've been further reduced to 3 for $5, including the corresponding conditioners