I keep track of all of my purchases in a spreadsheet which also tabulates monthly and year-to-date totals. Here is a screenshot, showing the March #s for Walgreens, CVS, WalMart, Target, Kroger, Randalls, Central Market, and HEB.
Regular price: $1,352.01
I paid: $178.34
I saved: $1,173.67 or 87%
Not as good as the last 2 months, but this was the first month this year that we were in town the entire month.