50. Always Have a Shopping Plan

Don’t ever go to the store without a shopping plan, be it a grocery run or a holiday shopping spree. Make a list of what you need to buy, the amount of money you’re willing to spend (but no more so that you’ll be forced to avoid all temptations), and bring all your coupon codes with you.
If you can, avoid buying from just one place. By diversifying your shopping locations you’ll be sure to find better deals. If item A costs more at Walmart, consider looking for an alternative elsewhere!