I haven't had a chance to look around yet, my local butcher in the shopping centre charges that, if I can get it cheaper still I'll keep an eye out.$10/kg for chicken breast is not cheap. I get it for around 7 but I'm in Sydney. Perth seems expensive or you have not looked around
Does Perth have Aldi? they stock bulk chicken, beef and mince at very cheap prices. Just bag them up and freeze them for later usage.
protein powder per gram of protein is actually cheap..