There are several things to keep in mind if you want to save money on groceries. First is the necessity of budgeting. I have written about it before in detail in this article. If you work out a budget and stick to it, it will considerably reduce your expenses.
The second thing to do when money is tight is to try and reduce your consumption. To do it effectively you'll need to differentiate between needs and wants. For instance, potatoes are a need, a bag of potato chips is a want. The same goes for candy, chocolate, chewing gum, soda, alcohol and the like. Those things are not wrong in themselves but they are not necessary for your daily functioning, either. A glass of wine by dinner is a luxury, and no child ever died due to being deprived of snickers and cola.
Third, you can try to switch to cheaper brands. A supermarket usually has its own brands which tend to be the cheapest. The difference in price is often considerable. For instance, biological jam in a special shop can cost as much as 3 euros per jar, while the cheapest supermarket brand is 85 cents. The same goes for coffee and other things.
Convenience foods and ready meals which need only to be heated tend to be more expensive. Also, sometimes it can be cheaper to bake your own bread. Learn to calculate the cost of the meal made of fresh ingredients and compare it with the convenience food equivalents.
Build your menus around sales. Don't go for fancy recipes with exotic ingredients. Simple food can be nutritious, too. Cook with the ingredients which are in season. You can also try farmers' markets which often have lower prices than supermarkets.
Substitute cheaper ingredients in your recipes for more expensive ones. There are some things you won't wish to go without, like fruit, but if it's very expensive, you can substitute it with tomatoes, or dried fruit which can be used in breakfast cereals. Switch to low-fat milk and if money is really tight, consider using margarine and various bread spreads instead of real butter.
If you have small children, make your own meals for them instead of buying insanely expensive baby food. If you don't know how, Google is your friend. The same goes for pets, you don't really need to buy expensive pet food. I'll admit that it's convenient, but if it really costs you a lot of money, you'll probably want to consider cheaper equivalents or find out how to make your own.
Don't buy paper towels, use cloth instead. You can also use old newspapers or advertisement fliers. Instead of buying juice for your children, think of using syrup which can be mixed with water. Plastic bags for cat litter boxes tend to be rather expensive nowadays, but can be substituted with regular garbage bags. Soap bars last longer than liquid soap in bottles, and meat from the freezer is cheaper than the fresh one. The same goes for vegetables, if the fresh vegetables are too expensive, buy canned or frozen instead.
When a product which you regularly use is on sale, stockpile on it. Potatoes can be expensive, too, but you can substitute them with rice, beans, pasta or bread. You could also consider reducing the amount of meat you eat as a family. While meat is important, and I would never suggest going completely vegetarian, you don't have to eat it every day to stay healthy. It can be substituted with fish, eggs or cheese, or you can reduce the amount of meat per portion but add cheese or eggs to your dish to compensate for the protein loss.
When you are doing shopping, have a list of all the things you need and stick to it, avoiding the temptation to buy unnecessary stuff only because it's on sale. Practice self-control and learn your children to do the same. A good housewife is a good manager who can make her husband's paycheck go a long way, if necessary.
We all have been through difficult periods in our life when we had to watch every penny. Saving money is an art, and if you have a proper mindset you'll start finding your own ways to economise. Remember, a penny saved is a penny earned!