I find it cheaper to go to Costo once in a while and buy a big pack of meat and then split it up into two person servings and freeze when I get home.
I usually shop around for sale items by looking at flyers and at on-line flyers. Not sure if any of you Canadians have these shops near you but we have them in Ontario - Basics (but bring your own bags or boxes with you or you have to pay for them) and Produce Depot - I can usually get fresh fruit and veg cheaper there in the winter time. There dairy and other grocery items are kind of pricey though.
In the summer I frequent the farmers markets - broccoli is 50 cents a bunch there as opposed to the supermarket that charges up to 1.49.
I also shop once per week and meal plan so that I only buy whatever fruit and veg I need for the week. Everything I buy has to fit into the meal plan so it doesn't get wasted. If there is no plan for it we don't buy it.
Also some of the discount brands are just as good as the name brands (my exception being Kraft peanut butter

)
We also buy a lot less pop and junk than we used to and I started baking my own cookies and baked goods when the mood strikes me. It is cheaper and at I can make healthier versions of what is in the stores.
I make a lot of stir fries and pasta toss meals and fill them full of veggies to stretch out the meat a bit more or just make them vegetarian. I also make chili, stews and casseroles in the winter and freeze any leftovers for future use. Use chicken bones and leftover meat to make soups so that nothing goes to waste.
At the end of the summer when the produce is really cheap and the local farmer's market is clearing stuff out to close down for the winter we load up on things like cauliflower, green beans, yellow beans,broccoli and carrots, etc. and blanch and freeze them at home.
It also helps to eat seasonally as these items will be cheaper than imported items that are out of season.