Once you decide How Often To Shop, you need to make sure you bring with you THE TWO C'S: CASH and a CALCULATOR.
Bringing CASH is a great way to make sure you stick with your budget. If you only have a certain amount of money with you, than that is all you can spend. Dave Ramsey speaks about a cash envelope system and we do a version of that. We relish the fact that we can't overspend and are living within (actually below) our means.
One concern with cash is that it will disappear. Either it will get piddled or lost. If that is a concern of yours, go to the ATM on the way to the store. This way, you will have less time to spend or lose the money.
Another thing to consider is how much of your budget to take with you. If you have a $125 budget, but you plan to shop twice that month, you should only bring with you half of the money. Earmark the rest of the budgeted amount and put it away where you know it won't be spent.
A CALCULATOR is a great way to be sure you are only going to spend what you brought. Making sure that you take the time to enter every single purchase. When adding up, do not forget to account for tax on taxable items. Also, try to get as close to the amount on weighed items as you possibly can. For example, if bananas are 50 cents a pound, and you buy 2 and a half pounds, you would add $1.25 to your total.
Leave yourself a little wiggle room at the end. You'd much rather get up there and have a total of $123.86 with a budget of $125 than get to the end and have to put items back because you do not have enough money with you.
If you are unwilling or unable to bring cash, a calculator can still be a way to ensure you stay within budget. At the very least, you will be able to see how items add up as you fill up your cart and won't be shocked by the total at the register.
Next Up...The Other C
Do you bring cash and a calculator when you shop?
Check out the other posts in this series: Say What!?!?!, Exceptions, Plan Before You Go, Where To Shop, How Often I Shop