What's a Price Book you ask? Well, it's a list of grocery items and the best price you've paid for them! With this record, you can tell where your commonly purchased items are typically the best priced as well as if stores are buffering their sale prices (marking them higher so you think you are getting a better deal than you are when they are on sale). I spent a couple hours working on an Excel Spreadsheet for this exact reason and when I came across this AWESOME spreadsheet from uncommonwaytowealth.com (disclaimer: I've only checked out the PriceBook spreadsheet so I am not endorsing their other ways to manage debt/finances!) and spent another couple hours with my past receipts to get started.
Seeing things broken down in black and white like that gives you an interesting insight into how your money is being spent! Only after inputting my purchases, did I come to find out that one of the items (Frozen Boneless Skinless Chicken Breasts) I typically waited to go to Costco for is actually $0.46/lb more expensive than when it's on sale at Safeway! Now I know when chicken is on sale at Safeway for $1.99, it's actually a better deal! I used to kick myself for having to buy chicken at Safeway, always thinking it was so much more expensive! Now I'm REALLY kicking myself.