THE "Rules"

My basic mantra is "Don't pay full price for anything"

Whem something is on sale really cheap, or at the lowest price it has been in the last six months, I buy  1)  as much as the store will let me buy  OR  as much as I can afford to buy  OR as much as I
can safely use before the expiration date or when I think it will go on sale again.  Storage of shelf ready goods can be creative when the savings is remarkable.  I look at it as if being a minimalist means that you can burn seventy five dollars a week and feel good about it....go for it. 

Start a small spiral bound notebook .  Put the items that you buy frequently on the top of the page, one item per page include the size of the package.

On the lines, put the 1) date you purchased the item  2) the store you purchased it from (use shorthand)  and the price you paid for it.  Soon you will begin to see how much the cheapest price is. 
I recently got Stag Chilli , even the vegetarian kind, for .50 a can.  Stag chilli is 1.59 and the usual sale price is a buck.  I bought 15 cans....(camping season is upon us )  .  I won't buy it again until it
goes on sale.  If we run out, we use an alternative. 

I stock anything that we use enough of .  Things with a short shelf life I keep one ahead, so that I
don't have to run to the grocery store when I run out.  Pasta has a EIGHT YEAR shelf life!  Can goods usually have a 3-4 year shelf life, except canned meat, and fish.  

If something is really really cheap because it is close to its expiration date, ( many things are sell by) I just use it immediately or I don't buy it. 

I almost NEVER buy junk food out of my grocery money.  If there is only good food in the house, the family will only eat good food.  This is expecially important if you have a picky eater. 

If I find that our stock of something is growing to fast, I hold off buying any until it dwindles and I find another sale. 

Not everything that the grocery store flyers say is on "SALE" is really on sale. If you religiously
follow the "PLAN"  there comes a time, when you really don't have to grocery shop for a week other than fresh foods. 

There are storage solutions that keep your produce fresher longer.  Invest in them if you can, they will save a bundle of money. 

Also, make the investment to get the tools you need to cook from scratch efficiently.  They will pay for themselves in the long run.  If you can't afford to buy them at the regular store, look at estate sales and garage sales . Old people are downsizing all the time and have to get rid of their countertop appliances.  Or save up for them.  Invest the money you save on groceries to make more money. 
That is what they call the snowball effect.  If you take the money you save on groceries and purchase a tool to help you save more time and money, it snowballs into a sizable amount of money over the years.  Fifty dollars a week times 52 weeks is 2600.00 a year.  Enough to go on a vacation or put into your kids college fund, or simply pay for some of the utilities.