Use your calculator and take cash!

The calculator is an essential tool in a frugal lifestyle, especially when shopping. Using your calculator as you go through the store helps to keep you focused on how much you are spending and keep you on budget. Furthermore, if you take only cash to the store, you can only spend what you actually have and not be tempted to go over budget. I tend to go through phases of doing these, but I always do better at the store when I use both.

Also, I'd suggest when using coupons, add up your dollar amount before you check out so that you can quickly tell whether the cashier properly entered all the coupons.