I try and avoid the big box stores but shopping at Costco can save you a lot of money. Their meat department is great; they have a wide selection including a variety of beef, pork, chicken, etc. They have two cuts of ribs including baby back ribs which can be hard to find if you don't go to a butcher. I consistantly stock up on Kirkland brand extra virgin olive oil and their giant bags of basamati rice. Both are good quality and a great deal.

Prescriptions are cheap because the dispensing fees are much lower than other pharmacies. The optical department even has an optometrist on staff but somehow getting a prescription for glasses at Costco seems wrong.

They are starting to carry more environmentally friendly products including eco washing detergent but if you are conscious of these kinds of things, you definately have to be weary of many of their products. The produce is all shipped from the US so I generally avoid it; its not the best value anyways.

The best time to shop here is during the week in the mid afternoon. You definitely want to avoid on the weekend because it gets very, very busy. Overall, Costco is a great option for specific products if you are familiar with their stores.