We all have to eat, but shelling out for groceries each week when your budget is already stretched thin can be excruciating. On average, American families spend $151 a week on food, according to Gallup, and that number can easily increase if you have a larger household or the cost of living in your hometown is high.

But while groceries are a major expense, they’re not necessarily a fixed one. If you’re on a tight budget, here are some tips and tricks for reducing your weekly grocery store bill.

1. CLIP THOSE COUPONS (AT LEAST DIGITALLY).

“Don’t meal plan based on what you’re craving,” Kendal Perez of Coupon Sherpa tells mental_floss. “Plan your meals based on what’s on sale at the places you shop. A site like Flipp.com makes it easy to compare circulars between stores, or find the best price for an item using their search function. You can also create a grocery list using their app.”

Once you build your grocery list, you can search for coupons for even bigger discounts. And no, you don’t have to spend hours on end clipping: Most grocery chains have store-branded apps that make couponing easy. Download the app, link your store loyalty card, and just add any coupons digitally. The coupons are loaded to your card and automatically applied at checkout.

2. BUY WHAT'S IN SEASON.

"You can save 30-50 percent on the price of produce by buying what's in season," Annette Economides, co-author of Cut Your Grocery Bill in Half with America's Cheapest Family, tells Money. When these foods are in abundance, grocers want to get them off their shelves before they go bad and therefore keep the prices low.

Not sure what's in season? Check out this list from the USDA, or use this interactive seasonal ingredient map from Epicurious. You can then plan your meals around these cheaper ingredients.

3. AVOID WASTING FOOD.

The average American family throws away $2275 in food every year, according to 2012 statistics from the National Resources Defense Council. Do you feel like you have an extra two grand to literally throw away?

“The single best way to avoid food waste is to invest in a small deep freezer,” says Kyle James of Rather-Be-Shopping. “You can get a good one from Costco or Lowe's for about $160. It'll allow you to freeze food before it goes bad, but more importantly, it'll allow you to stock up on proteins like chicken, pork, and beef when they go on sale. For a growing family, this savings alone can easily save you hundreds of a dollars over the course of a year.”

What’s more, many people are too quick to toss out food. A study from the Harvard Food Law and Policy Clinic (FLPC) and the Natural Resources Defense Council (NRDC) found that "40 percent of food in the United States goes uneaten—resulting in waste of at least 160 billion pounds of food each year." The main culprit for this food waste, the study found, is the confusion caused by "best by," "use by" and "sell by" labels.

Sites like Eat By Date use information from the United States Department of Agriculture and the Food and Drug Administration to offer a more accurate view of your food’s lifespan. And instead of throwing those ingredients that are indeed nearing their expiration dates into the compost bin, toss them into a stew. “One of the best uses for aging produce is in soups and sauces, because they don’t have to be perfectly crisp in these dishes which typically render them a bit soft,” Perez says. “When you notice tomatoes and bell peppers looking soft and wrinkly, consider making spaghetti sauce or soup of some kind.”

4. WORK WITH WHAT YOU HAVE.

The “Pantry Challenge” asks frugal shoppers to optimize the ingredients they have at home to make complete, tasty meals. “If you’re on a super tight budget or find that you’re out of funds well before payday, take the pantry challenge and try to create meals based on what you already have until your pantry is cleared out,” Perez says. “You’ll likely be surprised how many dishes you can prepare with what you already have on hand!”

Online tools like SuperCook work well for this. The site suggests recipes based on specific ingredients, so you can list the items you already have on hand, and SuperCook will come back with a handful of recipes you can make based on those items. Better yet, you can sort these recipes by specific meal types, like dinner or breakfast, and by cuisine, like Asian or Mediterranean dishes.

5. LOOK FOR VERSATILE INGREDIENTS.

In general, it’s easier to plan meals on a budget when you stick to easy recipes with a few simple ingredients. “Typically, the simpler the meal, the less costly it will be,” Perez says “When you prepare meals with multiple ingredients, spices, sauces, and other additives, you’re just adding to the cost.”

In keeping meals simple, it helps to have versatile ingredients, too. Look for inexpensive, healthy food items that can be used in a variety of recipes: lentils, eggs, sweet potatoes, and brown rice, for example. And you can get quite a bit of meal mileage out of chicken, especially an inexpensive pre-cooked rotisserie from the grocery store. “A traditional chicken dinner can easily be made into chicken sandwiches, salads, or stir-fry later in the week or for lunch,” Perez says.

If you don’t already own one, consider investing in a slow cooker. Not only do they make meal planning easy, they’re also ideal for making batch meals out of inexpensive ingredients. “Beans can be cooked in a slow cooker or in a pressure cooker, the latter of which can only take 20 minutes to prepare if you soak them in hot water and salt overnight,” Perez says. “This is probably one of the cheapest, most satisfying meals people can have.”