If you're serious about saving money, it's important to focus on costs you can control. Some items may claim a large slice of the budget pie, but they're either fixed or relatively inflexible (like mortgage and utility payments).

By contrast, grocery costs are often more controllable and considered a variable cost. Careful planning and a little discipline when cruising the supermarket aisles can generate hundreds of dollars in savings.

Here are five suggestions for taming your grocery bill:

1. Avoid prepackaged foods. Bagged salads or prepared foods may save time, but they often exceed the cost of individual ingredients. Instead of buying boxed or prepped meals, purchase the ingredients separately and make it your own. Prep some of your own meals or components once a week or freeze meals monthly to save time and expense. Having meal options ready to go will help curb the need for take-out or pricey meals at restaurants.

2. Skip the impulse buys. Energy bars, bottles of soda, and travel-sized items are often impulse buys. That's why marketing departments place them at eye level usually near the checkout stand. If you really need one of these items, it's often more economical to buy it in full-sized packages — not just as one-offs. Also, using grocery pickup or delivery can help minimize in-store impulse buys.

3. Buy generics. Most food and household items now have quality store-brand counterparts or generic brands that closely or almost identically match the name-brand items. Buying generics or store-brands is an instant way to lower your grocery bill without doing too much planning.

4. Use digital coupons and app discounts. Coupons can make a huge dent in your grocery bill especially on items you regularly purchase. Digital coupons make it easier than ever to save some money. You can usually find coupons or discounts online and on store apps, as well as in the classic Sunday newspaper coupon supplement. As well, shopping the weekly ad can help you stock up when loss leaders are on sale.

5. Restrain yourself at the warehouse store. Bulk-purchase stores offer great deals, but the cart total can add up quickly. However, buying in bulk doesn't always translate to savings based on your family's needs. Consider whether a better or comparable price is available at your local supermarket, especially when coupons or sales are available. And don't fall into the trap of buying more than you really need, just because the unit price is cheap. Six months later, when you're throwing away an unused portion of food, you may wonder whether the bargain purchase was really a deal.