From its website:

What is it?

MoneyBackCo is the original Australian 100% moneyback/cashback website, where the consumer is in control. Instead of losing all or a vast majority of referral money that online businesses pay to attract customers to their website, you get to know exactly what the companies are offering referrers and the best bit is you get that back rather than someone else, and you receive 100% (after a $10 membership fee has been deducted from your earnings).

Basically when you buy something at an online retail shop, there is a possibility that a portion of it goes to an referrer who introduces you to this shop, as commissions/kickbacks. What MoneyBackCo tries to do is be that referrer, and try to return as much commission it collects from the shops back to the shopper as possible. There is no special deal between the shops and MoneyBackCo. You don’t get instant discount when you flash your MoneyBackCo membership card at check out. You just get a part of your purchase amount back when MoneyBackCo gets paid by the shop (usually 2 months after the transaction).

Now why do you see MoneyBackCo on OzBargain? We are actually two separate websites, but I felt this service is beneficial to the members of this site so I am promoting MBC here.