Non-perishables. I buy family packs and either break them down or store them. For example, toilet paper – instead of buying a 4-roll pack I’ll buy an 18-roll pack (saving $3.50 – or more if it’s on special) and so on.
I used to buy a 1 litre carton of milk each week. Now I buy a 2 L container of milk fortnightly and freeze a litre. The simple approach saves $1.20. Not a lot of money but as food prices rise all the time, it helps.