Apparently, you’ve either never heard of ovo-lacto vegetarianism, or you don’t consider it to be vegetarianism.
Anyway…I have some friends who were on an extremely tight budget when they were newlyweds, in Dublin (she had just graduated from college, and was working as a secretary; he was still in school). They swore by big bulk bags of lentils, beans, and rice.
We do the same but on Saturday for a Sunday shopping, since the Sunday paper has some additional coupons and sales in the Safeway ad. Not only do you save by planning menus by the specials, with a list you tend not to buy junk, you are out of the store faster, and you save money on gas by not going to the store 3 times a week to pick up that missing ingredient. Also, having the food ready reduces the use of takeout.
We buy things like coffee in large quantities when it is cheap. We have 19 bags of Starbucks in our garage now, Our store often has meat way reduced for the last day of sale - it is how we buy lamb and veal.
Farmers’ markets are usually cheaper and better than the supermarket. I used to work near a little bread factory which had a store in front which sold Orowheat and Entemann’s stuff for half price - plus you got something free if you bought $7 worth, and you had a card which gave you two free items when you spent $25. It is the wrong direction from where I work now, but it was a shock to pay full price for bread.
Voyager, your coffee beans will keep much better in mason jars than bags.
Separately, I’m a little thrown by how many people chip in with their tips on buying thoroughly processed and prepackaged stuff. Eating well and eating cheap do not have to be mutually exclusive. Hell, for me, they go hand in hand. Meaning that if I was going to not watch how much I spend, I might as well eat like crap while I’m at it.