Last month, I compared the price of Frosted Mini-Wheats at Costco and Safeway.

This past weekend, I stopped by Wal-Mart to shop around. Wal-Mart sells an 18 oz. box of Kellogg’s Frosted Mini-Wheats for $2.33, or $0.129 per ounce. Costco is still the store to beat, but you have to buy a 70 oz. box. For 70 ounces, the Wal-Mart price will be $9.06, compared to $8.49 at Costco. So, I can save $13.71 a year if I can finish two 70 oz. boxes a month.

Summer is a great time for corn. Every week, I buy 10 ears of the freshest corn for $6.00 from the Mountain View Farmers Market. The yellow corn is the sweetest, but the white and the bi-color corn are delicious as well. Unfortunately, during the week, I have to turn to the canned corn stored in the pantry. Not as fresh and sweet as the corn from the Farmers Market, but it’s corn.

Even the mutant corn is sweet. However, the extra appendage was worthless.

Piazza’s sells a 15.25 oz of S&W Whole Kernel Corn for $1.69.

Costco sells 12×15.25 oz cans of S&W Whole Kernel Corn for $9.39, or $0.783 per can, which is less than half the price at Piazza’s. And, those 12 cans have quite a shelf life, so buying a 12 pack makes sense if you enjoy corn. I really wish Costco will sell cream style corn. That goes well with everything.

I read an interesting article on Time entitled Why Exercise Won’t Make You Thin. The problem occurs when you “reward” yourself after a workout. All of a sudden, the calories that you had worked so hard to burn are quickly replenished by a treat or a sports drink.

The same rule applies when shopping at Costco. If you reward yourself for shopping at Costco, all of your hard-earned savings can quickly vanish. While you can save money by shopping at Costco, the total amount saved may only be several hundred dollars a year. And, if you pay $3.00 for a tasty cup of coffee or chai tea latte at the local coffee house a couple times a week, your savings at Costco have just vanished.

Pay attention to the quantity, not just the price. At first glance, I thought Costco was selling Kokuho Rice at a higher price than 99 Ranch. After all, a 20 lb. bag of rice doesn’t look too different from a 25 lb. bag of rice, especially when both bags are not next to each other.

So, Costco is selling a 25 lb. bag of Kokuho Rose Extra Fancy Rice for $20.99, or $0.840 per pound.

99 Ranch sells a 20 lb. bag of Kokuho Rose Extra Fancy Rice for $16.99, or $0.850. So, for 20 pounds of rice, 99 Ranch charges about 20 cents more for the entire bag of rice. Not a whole lot, but still more than Costco.

Costco sells a 70 ounce box of Kellogg’s Frosted Mini-Wheats for $8.49, or $0.121 per ounce.

Safeway sells a 24 ounce box of Frosted Mini-Wheats for a new low price of $4.49, or $0.187 per ounce. Wow! So, Costco is saving me $4.62 per box, compared to the Safeway per ounce price.

If I consume 2×70 ounce boxes per month, my annual savings is $110.88.

Costco sells an expanding mix of Asian foods. In addition to Ling Ling potstickers and jasmine rice, I have also seen edamame, shrimp won ton soup, and steamed pork buns. During my latest visit, I spotted a 32 ounce bottle of Lee Kum Kee Premium Oyster Sauce for $6.89.

So, how competitive is the cost of Asian food at Costco compared that from an Asian supermarket?

99 Ranch sells an 18 ounce bottle of Lee Kum Kee Premium Oyster Sauce for $3.99, or $0.222 per ounce. The Costco per ounce price is $0.215. To be fair, I should be looking at the price of the 32 ounce bottle at 99 Ranch, but I could not find it stocked on their shelves. I could only find a large bottle of the LKK Panda Brand Oyster Sauce at 99 Ranch.

99 Ranch sells all varieties of Berkeley milk for $3.79 per gallon.

I can taste the difference between different brands of ice cream and yogurt, but milk is pretty much milk to me. So, one gallon of homogenized milk for $3.79 at 99 Ranch or two gallons for $3.99 at Costco? Even if you cannot finish a gallon in a week, two gallons at Costco seems to be the way to go.

Costco sells Kirkland Signature homogenized milk 2×1 gallon for $3.99 and Kirkland Signature nonfat milk 2×1 gallon for $3.19. You have to buy 2 gallons at a time. No mix and match, unless you visit the Hawaii Kai Costco where you can purchase individual gallons. However, the pricing will probably be different.

Safeway advertises Lucerne Milk 2×1 gallon for $4.28 for whole, 2%, 1% and fat free. You can mix and match if people in your household prefer different types of milk, so you are not committed to buying 2 gallons of the same type of milk.

Finally, Piazza, a Palo Alto supermarket, offers Our Dairy Milk for $2.00 per gallon with coupon. You don’t have to buy two. In fact, you are limited to a maximum of 2 gallons. In this comparison, Costco has the lowest prices for milk. If your household can finish 2 gallons of nonfat milk per week, you will save $0.81 per week over Piazza’s advertised special and $1.09 over Safeway’s everyday low price. In a year, that represents a savings of $42.12 to $56.68.