We have a separate fridge and a separate freezer at home so we
usually do a big meat shopping and store them in the freezer which
can last the 2 of us for 4 - 6 weeks.
As for toilet papers, detergents, soap, shampoo, toothpaste, etc,
they usually last for a bit so we don't need to get them very
often.
So our weekly grocery shopping usually consists mostly perishables
like vegies, fruits, milk, yoghurt, bread (even that we usually buy
a few loaves if it's on special to freeze them in the freezer) etc.
However, we tend to buy other stuffs too like chips, cookies....
whatever we are craving for at that time
. So my piece of advice - NEVER GO SHOPPING WHEN
YOU'RE HUNGRY!!!
Still, our weekly grocery bill can add up to at least Aus$50 or
sometimes under Aus$100 depending on what we need or get on that
week. It's never fixed. 
Yes, things are getting really expensive nowadays!!
