Costco vs. Amazon: Who Has The Best Deals?

As both a Costco and an Amazon Prime member, I've been wondering who has the best deals on the stuff we regularly buy. Costco is well-known for its bulk sizing and Kirkland-brand private label products, while Amazon has Prime 2-day shipping and multi-unit, brand-name offers at prices that often undercut what you can get at physical stores.

I went to Costco yesterday and inventoried the stuff we usually buy.

Glide floss, 6 count	$12.99
Pacific Natural Foods Chicken Broth, 6 units of 32oz each	$9.79
Dave's Killer Bread, 2 loaves	$6.99
Kirkland Organic Peanut butter, 2 jars of 28oz each	$7.89
Fage 0% Greek Yogurt, 35.2 oz	$5.79
Cascade Dishwasher Gel, 125oz	$8.99
Kirkland Paper towels, 12 rolls of 80 sheets each	$14.99
Kleenex square boxes, 12 boxes of 85 sheets each	$15.49
Kirkland baby wipes, 900 total	$18.99
Ziplock quart freezer bags, 4 boxes of 54 each	$9.69
Ziplock gallon freezer bags, 4 boxes of 38 each	$10.79
Kirkland diapers, size 5, 168 total	$37.99
Kirkland toilet paper, 36 rolls at 425 sheets per roll (1912 sq ft)	$17.99
Laughing cow cheese, 4 wheels	$8.35
Total	$186.72

Next, I looked for comparables at Amazon. Here's what I did:

• I looked for the exact same brand and product. When it wasn't available, I went for something comparable.
• When the amount of product on Amazon differed from Costco, I went with a per-unit pricing (ounces for the yogurt, square feet for the toilet paper).
• I always went for Amazon Prime products.
• When the product wasn't available at Amazon, I priced it at AmazonFresh (as in the case of the yogurt).

Here's the comparison chart:

	Costco	Amazon	AmazonFresh	Notes
Glide floss, 6 count	$12.99	$20.28
Pacific Natural Foods Chicken Broth, 6 units of 32oz each	$9.79	$18.66
Dave's Killer Bread, 2 loaves	$6.99		$10.98
Kirkland Organic Peanut butter, 2 jars of 28oz each	$7.89	$8.82		Substituted O Organics
Fage 0% Greek Yogurt, 35.2 oz	$5.79		$9.18
Cascade Dishwasher Gel, 125oz	$8.99	$12.49
Kirkland Paper towels, 12 rolls of 80 sheets each	$14.99	$22.15		Substituted Bounty
Kleenex square boxes, 12 boxes of 85 sheets each	$15.49	$28.79
Kirkland baby wipes, 900 total	$18.99	$25.00		Substituted Earth's Best
Ziplock quart freezer bags, 4 boxes of 54 each	$9.69	$16.49
Ziplock gallon freezer bags, 4 boxes of 38 each	$10.79	$26.94
Kirkland diapers, size 5, 168 total	$37.99	$41.28		Substituted Earth's Best
Kirkland toilet paper, 36 rolls at 425 sheets per roll (1912 sq ft)	$17.99	$31.39		Substituted Cottonelle
Laughing cow cheese, 4 wheels	$8.35		$19.56
Total	$186.72	$292.01

As you can see, Amazon comes out to over a 50% premium to Costco. In fact, I found not one product that was cheaper via Amazon. Add to that the $79 Prime membership versus the $50 Costco membership, and the disparity grows.

Am I going to give up Amazon Prime? Nope. Amazon has plenty of stuff that Costco doesn't have, and at good prices compared to traditional retailers. But for many things, Costco's combination of private-label products and bulk sizing yields way lower prices. So, I'm sticking with both.