I agree with Phil, Bursons are a good alternative.
I have worked for an Auto parts wholesaler that also sold to the public. Trouble with Repco (and other Australian retailers) is that they are buying their parts after 1 or 2 middle men have charged their own mark ups on the parts. After the retail markup is added, things can start to get a bit silly price wise.
I buy a bit of stuff from Burtons in the UK because the price is better, I know the parts will be reasonable quality, and I'm confident they know their stuff. I also buy from my local AutoPro which is great, and a store in Canberra called Motor Spares which is mainly wholesale/trade sales with some retail (these guys really know their stuff).
Cheers
Jamie