rents in sydney have gone up lately.more people but not more houses.
3 br rent depends critically where in sydney
if you go out west say 20 km and catch train (medium to good service 50 mins in air conditioned train around $10 each way cheaper if buy 1-3 months ticket)
then rents are $200-250/week. closer in rents are $350-600/week depending on the area.
difficult to drive if then on top of driving time ( 45mins-1hour using part expressways and $4 toll each way ) you have to pay parking fee in CBD around $20-40 per day.

education is expensive if not government funded school or church school (usually catholic and often expect you to confirm your kids into that religion but excellent standard and discipline compared to govt schools and for little cost)
non govt /non-religious schools are around $20,000 per year for each student plus extras so often on a par with price of small house after 6 years of study for 2 kids!! bit of a ripoff in my opinon(I chose the expensive alternative and felt let down by the school). many opt for cheaper schools or move nearby a selective government school to be allowed in ) but pay for special tuition around $40 /hour per subject tutored.

stan