My wife and I have been trying a new trick at the supermarket I call counting groceries. It is actually a lot easier than it sounds and has been working quite well for us. Before, we would show up at the check stand with an overflowing cart, crossing our fingers and hoping for the best. Now we simply count/add up the items as we go, and can tell the checker the total before they ring us up. I know it sounds difficult but if you can count to 100 than you'll be able to do this. The trick it to round to the nearest dollar or keep an even fifty cents.
Start with an empty cart, you add your first item a gallon of milk for $2.49. I say out loud to my wife $2.50. Next we get 3 tomatoes for $1.00 each. I say out loud $5.50. Next we get ketchup for $2.79. I say $8.50 because it is just easier to round $2.79 to $3.00. next we pick up three bananas for $0.45 each. I round each banana to $0.50, and say $10.00. Next we get a bottle of Ketchup for $2.19 round it down to $2.00 and say $12.00, Next we pick up a whole chicken for $2.77, I say $15.00......Ect. We continue on like this throughout our shopping, keeping track of the last number, before each new item. If you shop like us you will get to the check stand with a number like $92.00. simply ball park the tax and wait to see how accurate you are. Our tax rate here is around 9%, so I would estimate the total bill including tax to be around $100.00. The cashiers will look at you in astonishment, if you can regularly tell them the total before they even ring it up.
The benefit of this method is that there are no surprises during checkout, and you will actually start evaluating each item before putting it in the cart. Is this $4.00 bag of Cheetos really worth raising your total from $56.00 to $60.00? Try out this method once to see if you can do it. It makes shopping more enjoyable trying see how accurate you can be. If you don't want people in the store to look at you funny, you can also keep the totals to yourself, instead of saying them out loud. For me it just helps me remember the last number.
Let me know if it works as good for you as it does for us.