"A goal without a plan is just a wish." ~ Antoine de Saint-Exupéry
There are lots of ways to save money when buying groceries: coupons, shopping several stores to hit the sales, basing your menus on sale items, shopping only from a list, paying cash, not shopping while hungry, etc.
If you have an unlimited amount of money or you've decided that one place you want to have complete freedom to buy what you want is the area of food, then this post isn't for you. But if you have goals in your life that you're having trouble reaching because you tend to overspend on food, or if you have a very tight budget that you're trying to make work, then keep reading.
I think the one thing that has changed the way I shop and helped me make better decisions is this:
When I make my shopping list, I put a number in front of item--the estimated cost. And then I add up the numbers before I go. If I'm way off of where I want to be, I can back-track and put optional items in brackets or cross them off entirely. Then I make my new total. Once I'm happy with that figure, I leave for my shopping trip.
Once I'm at the store, I note the actual price of what I'm putting in the cart. I can go a couple of ways at this point: notice if it's over or under and keep a general idea of whether I'm staying on target, keep a rounded-off tally of the actual amount I'm over or under, or have a pen with me and write down either the prices or the difference so I can keep track.
This may sound really anal or like a lot of math. I tend to keep it as simple as possible for myself. I do find math fairly easy, so I'm not sure how it would work with someone more number-challenged, but the point is, you have an idea the whole time of how close you're going to keep to your plan, and I found that to be quite empowering actually.
So what happens if you see something that wasn't on your list? First of all, I always round up on my estimated costs, so there usually ends up being a natural buffer. Secondly, you may find items are significantly cheaper or unavailable or so jacked up in price, that you end up not getting them or they cost less. So you may run up a nice little surplus that allows you to pick up a couple of things you hadn't planned on. Another way to help out with this, is to create your own buffer before you go for unplanned items (whether they are something so cheap you want to buy extras or something you decide to splurge on).
As you can see, the principle behind the practice is not severe restrictions. It's a plan that allows you freedom while allowing you to keep track and make wise decisions.
The funnest part of the process is when you ring it through and you find out you spent almost exactly the amount you expected to spend. Or less! Some days, you may ignore your plan or be looser with it. That's up to you. But if it's important to you to stay on track so you can reach your goals, you now have a tool that can make that possible.