Clipping coupons may seem time-consuming, but they can save you 10 to 20% on your grocery bill. Before tossing out junk mail, take a minute to look for coupons you can use. Don't be so quick to toss coupons you get at checkout either — those are generally tailored to your purchasing habits, which means they're for items you already buy. Aside from paper coupons, many stores also have apps or websites with digital coupons that can be "clipped" to your loyalty card. When you use your card or phone number, the savings are applied automatically.

Up to 20% of a household's grocery bill is spent on impulse purchases. Creating a shopping list — and more importantly, sticking to it — can dramatically reduce this unexpected spending. Write down essentials, like items you eat a lot of or that have run out, and add meal ingredients to save yourself an extra trip. Finally, take inventory of your kitchen to make sure you don't already have too much of something. Some people find it helpful to keep a running shopping list so they can update it as soon as something runs out and cross off anything they picked up on an impromptu trip.

Weekends and early evenings, after the standard 9 to 5 work hours, are always going to be the busiest times at the grocery store. If at all possible, shop late at night or on weekday mornings. During off-peak hours, it's much faster and easier to get in and out of the store, plus you'll enjoy shorter wait times. There's also much less chance that any of the items on your list will be out of stock.

It sounds cliché, but it's true: don't grocery shop when you're hungry. Hunger affects decision-making abilities and if you shop with a growling stomach, you're more likely to make impulse purchases and choose higher-calorie processed or prepared foods you normally wouldn't. Not only can this derail healthy eating habits, but you're also going to spend extra money. Try to time your grocery shopping after a proper meal. If that's not possible, at least have a healthy snack and a glass of water.

If you want to stick to your grocery budget and list, you should shop alone. Studies show you're a whopping eight times more likely to make impulse purchases when shopping with others. Going alone eliminates temptation from others, especially children, asking for items that aren't on the list or even simply pointing out things that look good. Grocery shopping can also take substantially longer when you're shopping with someone else — again, especially children.

It's one of the oldest marketing tricks in the book: grocery stores place the most expensive items directly at eye level, where shoppers are most likely to look. Meanwhile, more economical options such as the store brands and sale items are placed on lower and higher shelves. Always scan the entire section, especially when it comes to staple items or other products where the brand name isn't important. You're much more likely to find a sale.

Did you know that generic store-brand products are often made by the same manufacturer (sometimes even in the same factory) as popular name-brand items? It's true! In nearly all cases, with the exception of a special promotion, generic items are less expensive than name-brand products. That's because big-name brands have fancier packaging and do tons of advertising — costs that get passed onto the consumer. Consider buying the store brand, especially for staple ingredients. You may be pleasantly surprised.

If you have storage space and room in your budget, consider buying certain foods in bulk. Pantry staples, particularly, typically make more sense to bulk-buy. Compare the cost per ounce, not per package, to decide. Similarly, if an item isn't sold in bulk but goes on a particularly good sale, buy as much of it as you can afford. It's important to buy only what you know you'll actually eat before the expiration date. You're not saving anything if you end up wasting food.

When you're checking out at the grocery store, watch the scanner closely as the cashier scans each item. Things could accidentally be rung up twice, prices could be incorrect, and sale prices might not be reflected accurately. These are all minor and common mistakes that could end up costing you a couple dollars each trip. That may not sound like much, but over the course of a year, it adds up and becomes substantial.