If you think a trip to the grocery store is expensive now, give it a year or two. Economists expect food prices to rise even more, due to the rising costs of base ingredients such as dairy, grains, meat and produce. Why? In a word: Oil. When the price of oil rises, the price of just about everything else follows suit. This is especially true for food, since the agricultural industry depends heavily on petroleum -- from pesticides to packaging to shipping.

But if you're looking to save money on groceries, take a closer look at your current grocery shopping habits. Are you already spending more than you have to? Quite likely, yes. And the culprit is usually convenience.

First, it's important to understand that when you buy a carton of soy milk, you're not just paying for the product, but you're also paying for the store, the heat or air conditioning, the lights, the staff, all of it.

And when you buy products with added value, such as ready-made frozen dinners, pre-cooked meats, pre-sliced cheeses or single-serving sizes, you're really forking it over!

Here are some easy tips that will have you saving money on groceries each week.

1. Buy food in bulk or family size

Think: Yogurt, drink boxes, soups, canned fruit cups and other items like this. There's more packaging involved, so it's going to cost more. Consider buying the bigger or family size and portioning it into containers at home. Now might be a great time to invest in re-useable drinking boxes, thermoses and other food containers.

2. Avoid pre-cut, pre-packaged meats, cheeses, fruits, veggies and herbs

Those plastic boxes of bologna, cheese and crackers are one of the worst offenders and are definitely not helping you save money on groceries. Any time you opt for pre-sliced, cut or shredded over doing it yourself, you're going to pay dearly for the convenience.

3. Eat fruits and veggies that are in season
The price of fresh, California strawberries in January is always going to be more than the price of local strawberries in June. Try to eat in-season foods and choose local whenever possible. Still, we all crave avocado, citrus and a juicy mango from time to time, so visit local markets in nearby neighbourhoods, where you're bound to get a better price.
4. Avoid name brands

Sure, we all have our favourite brands, but very often store brands and even no name, bargain brands are made by the same manufacturers. Proprietary products such as Coke, for example, are made from a patented set of ingredients and so, only Coke tastes like Coke. But, when it comes to many other products (from foods to household cleaners), the only real difference between a brand name and a bargain brand is the price.

5. Be cautious of fancy packaging

Think: Easy-pour spouts, re-sealable bags, airtight or breathable containers. Any 'special' packaging is going to cost a little extra. Twist ties and plastic storage containers can help you save money on groceries. Buy the product in the inexpensive packaging and transfer it into something more convenient (if necessary) at home.

6. Don't shop at convenience stores

Doing your groceries in a 24-hour convenience store is going to cost a pretty penny. Someone has to pay to keep the lights on 24/7! Getting to the grocery store in time just takes a little planning ahead. Save your trip to the corner store for that late night Rocky Road craving.

7. Don't buy bottled water

Buying bottled water is not going to help you save money on groceries. In fact, those terribly handy plastic bottles of water are going to suck you dry. Invest in an under-the-counter, on-the-faucet or jug-style filter and watch the savings start to flow.

8. Cook from scratch and avoid mixes

Cake mix, muffin mix, hot chocolate mix, you name it! If it's pre-mixed, it's more expensive than if you made it from scratch. And mixes often contain unpronounceable ingredients. Keep your pantry stocked with baking essentials so you have everything you need to bake, whenever the mood strikes.

By cutting out the cost of convenience, you'll have money to spend on what really matters -- buying the healthiest food available for you and your family.