Baby/child seats that support kids from 6 months to 8 years of age are typically bloody expensive.
This is on promotion at the moment at $324.79
Alternative prices for the same seat:
Supercheap Auto - $472
Infasecure.com.au - $589.99
Big W - $580
I wouldn't recommend forward facing at 6 months. Based on experience. Their posture isn't good enough.