In order to really start saving money, you have to know where you are starting and you have to know when a "deal" is really a deal -- for YOU. I recognize and appreciate fully that certain seasons of life, personal preferences, and other factors play into the amount of money spent at a store. That is perfectly, perfectly fine. What I believe is helpful in controlling your costs, even in a situation where you have limited time or resources, is to know (1) what is important to you and (2) work on getting your costs as low as they reasonably can be.
This is where a price book comes in handy. I'll give you a great example. Diapers; toilet paper; feminine hygiene products. This is an area in which one is, literally, throwing away money; the product is designed to be used once and then trashed.
Now, it is unquestionable that the most frugal and environmentally friendly option in these cases would be reusable products: cloth diapers, cloth wipes, cloth menstrual pads and reusable cups. You incur a one time only cost and the longer you use them, the smaller the cost per use.
That said, are you ever going to get me to give up my toilet paper? No. Nosiree. And will I judge you if your personal ick factor causes you to say "nuh-uh, no way" to any one of these options (though if you aren't icked out, as I said, they can be incredibly cost effective)? Noooooo. You and I are different people.
Let's say it isn't your ick factor, but other external factors that keep you from going reusable. Your kid is in daycare and they won't use cloth. You work and can't imagine using cloth pads outside the home. Your husband thinks you have gone mad when you suggest cloth wipes instead of toilet paper. Fair enough. We all have limits.
There are physical limitations, too. Some babies get rashes from a particular brand of diaper. They can only use a certain kind of wipe without a flaming hot diaper rash. Only one kind of toilet paper is appropriate for your husband's delicate nether regions. This is a perfectly legitimate limitation. Happy babies are a bargain. Happy husbands, too.
So you have determined your non-negotiables. Your job, at that point, is to determine how you can get the cost per use down to the smallest it can possibly be, because anything more than that and you are literally, actually throwing away money.
Bah, you say. What's a little loose change per diaper matter? Well, you'll change that kid at least 2500 times before she's potty trained. Multiply .10 times 2500. Two hundred and fifty bucks. Nothing to sneeze at. If you put that in the kid's college fund, it might be able to buy a semester's worth of books in 18 years. Multiply that times the number of kids you have.
Or take toilet paper. We never, ever (unless we are willing to go enviro-mental) stop using toilet paper during our lives. A few pennies per flush times 4 per day times the number of people in your household times 365 days times 45 years equals a really good start at a retirement fund.
Thus, you must determine your non negotiables and then work to get the cost per use down. That's why you need a price book.
Again, diapers. Your sweet munchkin can only use Huggies, par example. Regular price for a Huggies jumbo pack is 9.99 for 34 diapers. That is .29 per diaper. A quarter and four pennies every time you change your baby.
Can you wait for a sale or find a lower everyday price? Say, 8.99 per jumbo pack? That's .26 per change. You saved .03 per change.
If you can find a sweet coupon, say for $1.00 off, then you are at .23 per diaper. That's a .06 savings per change. A $2.00 off coupon (not unheard of) makes it .20 per change. Not bad.
Now you know what the cost per usage range is for your particular brand or product, and this makes it easier to assess the difference in cost between packages (mega?! super mega? boxes?) Divide the price by the number of diapers in the box, and you are there. The lower your CPU, the better off you are. And if you should happen to find a deal that is consistently the lowest CPU, that is where and when you should buy.
Now expand this knowledge to everything you use or consume in your household. How will you keep track of all those numbers? Your price book. You write down the highest and lowest number in the range for your product category in a little notebook, which goes in your purse. Thus, you can determine whether that "SPECIAL VALUE" box of Huggies on 15 percent clearance at the Target plus your high value coupon is really a good deal (sometimes yes, sometimes no). Or the jar of peanut butter, of which you use one per week. Or that loaf of bread, of which you use four per week. And so on.
But first, you must keep track, either in a little book or (if you are very very good or have been doing it a long time and know your prices dead) in your head. That is where you start. I recommend starting with the ten products that are on your list every single week. You know what they are for you. Bread. Milk. Diapers. Laundry detergent. Whatever they are, list them. Identify any preferences. Identify your regular cost per use. Then work to get that cost per use down.
I'll give my own final example. Milk. In this house we drink A LOT of milk. (Five kids. Four boys. ) A LOT. Can be up to four gallons a week, depending on growth spurts. So it's always on the list. But our family's limitation is that it must be 1 percent or less milkfat, and it must be artificial growth hormone free. This means no grocery store brand milk for me. Still, I can manage my milk cost to about $2 per gallon, sometimes even less, because I know my limitations and I know my prices.
How does this save you time? Well, if you know that your price target for milk is $2.00, and there is a sale on milk for $1.79, then by all means, buy enough for the week (or two, if you have room in your fridge and it won't go bad). Similarly, if the box of Huggies plus your coupon makes the diapers .15 each, then buy until you are out of coupons or money. You won't have to go buy diapers for a long long while. Conversely, if some yahoo on the internet tells you about a screaming deal you must get RIGHT NOW that makes your cost per usage .23 per diaper, you can determine whether you want to stop watching Jon Minus Kate plus Eight to hop in the car and get it, or whether you'd rather pass.
Similarly, let's say you are tight on time one week. (Been there, done that, nailed it shut.) You can assess whether it is worth your time to make a special trip to the store that has the lowest price on whatever, or whether you will just suck it up and for the week pay the higher price to save you time. Or, knowing you will be tight on time one week, you can buy up at lower prices the week before and sail through. The choice is yours. The beautiful thing is, you will be making a conscious choice, one that is well informed.
As I said, if you're new to all ths, start small. Start with the 5 or 10 things that are consistently on your buying list. Find out what you are paying for those things right now. Write that number down in your little book. Then work to see if you can get that number lower. When you find a lower number, note how you got it (with a coupon, at a different store, etc). Rinse. Repeat.