We are only 2a 1c and we probably average $100 a week, and that covers nappies (1 packet a month as mainly use mcn's), and most personal items as well. We do have a veggie garden and honestly that makes a massive difference (and we are getting chooks soon, cant wait!!) - a bit harder with a rental but there are lots of things you can grow in pots etc.

Being on such a tight budget we do shop the sales and buy marked down meat etc. For example we have found coles on a tues / wed here mark down a lot of thier meat, often up to 60%. So if we find a special like that we stock up, last time 4 star mince was $2.50 for 500g.. I think we brought all of the packets left and put them straight into the freezer (!) I think we have only just finished using it all. I have found having the per item price now on the shelf tickets a big help too, we are a lot more aware and compare different brands etc.

Meal planning is also a big help!

I would also check out $120 dollar challenge (14 meals and snacks - $120 fortnight), she has lots of fantastic recipes on her website.

Another idea, is also to do a complete stocktake of your fridge, pantry and freezer.. write it all down and plan meals based on what you already have (use websites like taste and best receipes to get ideas). You will be amazed by what you already have and can make from it. We do this once a month, it forces us to make sure we are using everything we buy!