99 Great Ways to Save Money: Save on Anything, Cut Costs Tips - AARP Bulletin
Make sure to check out the last link, tips from real people which has this gem:
Look at each $1 bill you get and note the letter of the alphabet in the circle on the left half. (These seals denote Federal Reserve regions and run from A to L.) Save bills with a letter of significance to you for specific purposes, such as C for a gift for Carol, or B for a new bicycle. You can easily save $500 or more a year without missing a dollar here and a dollar there. —Leita Spears, Waldron, Ark.
