Mrs Avraham
When we get paid I automatically put aside the maaser (tithe 10%) and the savings into the savings account (10%) and I use the rest to pay the bills, and then shop at the supermarket with what is left.
This means that I get really creative with seasonal (cheap) veggies, make my own challah (it's a mitzvah too!), and save the treats/snacks/nosh etc for Shabbos.
It can be a squeeze, but you can watch your savings grow! I also highly recommend to read Nechama Greisman