Comparison Shopping is HELL

I am admittedly not a comparison shopper, not someone who likes to grocery shop, not someone who enjoys the hunt. However, I have become more and more aware of how much prices fluctuate between (and even within) stores and wanted to look at it a bit more scientifically. Frankly, I found it overwhelming and confusing and after having done this teeny bit of research, found it not only more overwhelming and more confusing but additionally surprising and sort of depressing. 

I shopped at Target, Whole Foods, Traders Joe's and Shaw's. There are no Walmart's near me but I will eventually add them to the list, as well as BJ's and Costco.

So here's my conclusion: 
1. Buy a lot of basics at Target. 
2. Buy store brands, unless you are very loyal to a particular brand. For instance, I love Cabot Seriously Sharp Cheddar Cheese and the store brand is cheaper though not as tasty. In some cases it makes a difference and in some it doesn't. This is just a matter of what you like and what you are used to. Even Whole Foods 365 line, which I had assumed would be outrageously expensive, was on the whole (ha ha), much less expensive than the same ingredients at the more conventional grocery store. 
On the other hand, I am a huge fan of Grey Poupon mustard and get panicky unless I have a whole jar of backup. The Trader Joe's version is a fraction of the price and sharper to boot but since I love mustard, I don't mind the sharpness and am now a convert. On the other hand, the Whole Foods brand is also less expensive, but much sweeter, which I don't like.  
3. Buy what what you like when it's on sale. I have a friend who has plenty of money but grew up in a very large family and still builds her meals solely around what's on sale. Of course, you have to be able to think on your feet and you have to have a really great sense of what goes with what.
4. On the other hand, conventional grocery stores have the best in-store coupons.