Bacon: Bacon seems to go on sale 2 for 1, so I load up then and keep it in the freezer. The trick is to buy 2 or 4 when they are on sale (depending how much you use it!) so that you will never pay full price for bacon again.
Heavy cream: Heavy cream is often on sale at my supermarket, and is my favorite for this recipe, but you can also use half and half if you find that it's on sale, or if you have another recipe that can use the half and half (or you are a coffee drinker). Evaporated milk is also an option, although the flavor will be slightly different. If you buy heavy cream and have leftovers, you can use it to make whipped cream to dress up in-season (inexpensive) fruit for a dessert, or use a splash to finish pan sauces (for example, use instead of butter in my 4-step chicken). Note: If you are making numerous potato tortes for a party or as holiday gifts, the large heavy cream containers available at the warehouse stores often cost about the same as the smaller containers at the grocery store.
Gruyere Cheese: I buy a good quality cheese because it is so flavorful and nutty that a little goes a long way. Don't be afraid to ask the person behind the cheese counter to cut a smaller wedge than what is already available in the cheese case. If a smaller portion isn't possible, feel free to experiment with a cheese that is on sale: look for something creamy that will melt well, such as swiss cheese or mozarella. And don't forget, you can absolutely leave the cheese out, this torte is so satisfying that I promise you will love it without the cheese.
Butter: When butter goes on sale, I stock up on unsalted sticks and keep it in my freezer. Even if you don't have a lot of extra freezer space, one extra pound of butter can usually slip in a spot in the freezer door, and it will save you some money!
Mixed Greens: I let my produce department do the work for me, and I follow what they have on sale. I can say with near certainty that some form of lettuce or leafy greens will be on sale each week. And don't overlook the prepackaged section of greens – they go on sale 2 for 1 about once a month. I can't stock up in advance, of course, but I can be sure to include these greens on my menu a few times that week. (Remember: letting the sales help guide your weekly menu is a big money saver!)
Applesauce: This is one of those staples that just seems to go on sale like crazy, each brand taking its turn. I buy when cheap and keep an extra jar or two on hand. Even not on sale, though, applesauce will fit into a budget meal; just buy the unsweetened generic, and it will work great.
Yogurt: Dairy is marked down when the "sell by" date approaches. Usually the markdown happens in the morning, so that is when I load up on milk and yogurt. With four children, we have no trouble consuming dairy products in plenty of time before the expiration date! Yogurt is definitely something I buy marked down when possible. Or, consider making your own if your kids eat as much of it as mine do. Just making my own yogurt saved me $50 a month!
Maple syrup: Managing my family's food budget is all about saving where I can, and spending when it makes sense. Real maple syrup is worth the investment in our family because my kids love my husband's famous waffles on Sundays, so I didn't want my kids to consume the commercial maple syrup substitutes. I buy large bottles of real maple syrup to keep the per-ounce cost down (and I pour it into the commercial container, but don't tell my kids!). However, do not go out and buy a bottle of real maple syrup just for this granita! You can use honey or even brown sugar instead. Or, if you must, use a little "fake" maple syrup – it's only a tablespoon! You can also just buy a maple yogurt, or even just use vanilla yogurt in a pinch.