I'm in the Cronulla area.
I'm not a drinker so I can't help with the cost of the grog. Never really taken note of the price of bread for some reason!?!? Milk is about 3.75 for 2L. Petrol down our way is about average for Sydney- 1.09-1.21 at the moment depending on the week. Tuesday arvo/ Wednesday morning is the end of the cheap cycle. Decent meal? That's the nice part of the shire in that there are a plethora of places where you can get away with two courses and wine (for two) for about $70 or you can go tonto and splurge and spend a couple of hundred. The closer to the water(Cronulla), the more you pay generally. We have some really fantastic Thai restaurants around the place (not quite as good as Newtown but stilll pretty good), some decent Indians, Italian, etc, etc. I can provide some recommendations if you like too!
Rents are still relatively cheap but that won't last with upward corrections being noted all over the place. Domain.com.au will be your best bet for that kind of information though. If you want to buy then a knock down job will set you back about $650K in Woolooware- and that'd be on a relatively busy street. A three bed town house is between $520K for a smaller one through to upwards of $780K for a bigger one. Again domain.com.au would be the best bet.
Commute to the airport is 30-40 minutes from most parts of shire. Add ten to fifteen minutes for Engadine, Heathcote, etc.