If Canada is anything like the U.S. the snag I think you'll hit in establishing answers to questions like "what does this pound of butter cost at X chain" is th

If Canada is anything like the U.S. the snag I think you'll hit in establishing answers to questions like "what does this pound of butter cost at X chain" is that supermarkets now play so many games with pricing that there isn't one answer! 1. Prices may be regionally or locally varying based on, I assume, either inventory management needs or their idea of what people in one area will tolerate. 2. Pricing gimmicks. At my local supermarket, a standard bag of potato chips is $6.99 or so, but during some phases of the moon it becomes "$1.99 WHEN YOU BUY 4." Other products, a lot of packaged goods, go on sale in bundles: An item that may be $4.99 will be "$1.99 WHEN YOU BUY 5" participating products which may be chosen from certain unrelated stuff, like crackers, Tide, and Pillsbury biscuits. It's up to you to scrutinize the circular, the shelves don't always enumerate the eligible products. And finally, the best one, the "with digital coupon" prices. All you have to do is get on a sluggish app in terrible cell service, get properly signed in (oh, be sure to check your email because we needed to send you a 'security code') and locate and 'clip' the coupon and then you get a sale price. If you forget to do that you'll pay full price. So in the above situations I'm concerned what kind of data integrity one would get because different consumers will pay different amounts. For instance, not everyone has room to transport 4 bags of chips home, so they may end up spending $7 for 1 instead of $8 for 4. Therefore the chips are simultaneously $2 and $7.