Costco vs. Amazon: We Compared Prices for 23 Essential Summer Groceries

updated May 1, 2019
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It’s funny how your grocery list changes when summer comes around with all those al fresco meals and backyard cookouts. If you need to stock up, we’d be willing to bet you’ve considered either making a trip to Costco or logging onto Amazon. One has bulk offerings with low prices, while the other has oh-so-convenient, to-your-door delivery. Exactly how much more can that convenience cost, though?

We spent some time in these retailer’s in-person and virtual aisles to find out who has better prices on essential summer groceries. Read on to find out.

Note: Amazon prices change constantly and Costco prices vary by location. The Amazon prices were accurate during time of reporting and the Costco prices come from my location in Raleigh, North Carolina.

(Image credit: Christine Gallary)


1. Ketchup

For the same bulk package, Costco was way cheaper. But if you bought smaller quantities, Amazon got more affordable ($3.38 for 32 ounces), and if you got the 365 brand, it was quite a bit cheaper ($2.69 for 32 ounces).

  • WINNER! Costco Heinz Tomato Ketchup, $7.29 for three 44-ounce bottles ($0.055 per ounce)
  • Amazon Heinz Tomato Ketchup, $17.99 for three 44-ounce bottles ($0.136 per ounce)

2. Mustard

Oddly, I did not find stand-alone mustard at my Costco — they only had it in a pack with ketchup and relish.

  • Costco no mustard-only options
  • WINNER! Amazon 365 Everyday Value Organic Yellow Mustard, $2.69 for 14 ounces ($0.19 per ounce)

3. Mayonnaise

Both of Costco’s options are cheaper here, but your health might be the loser if you buy this much mayonnaise.

  • Costco Kirkland Signature Real Mayonnaise, $4.99 for 64 ounces ($0.078 per ounce)
  • WINNER! Costco Duke’s Heavy Duty Mayonnaise, $8.29 for one gallon ($0.065 per ounce)
  • Amazon 365 Everyday Value Mayonnaise, $3.99 for 32 ounces ($0.12 per ounce)

4. Hot sauce

If you need some heat, get it at Costco.

  • WINNER! Costco Tabasco Original Sauce, $4.99 for 12 ounces ($0.416 per ounce)
  • Amazon Tabasco Original Sauce, $21 for two 12-ounce bottles ($0.875 per ounce)

5. Salsa

You get a LOT of salsa for your money at Costco.

  • WINNER! Costco Kirkland Signature Organic Salsa, $7.79 for two 38-ounce jars ($0.103 per ounce)
  • Amazon 365 Everyday Value Thick & Chunky Salsa, $3.99 for 24 ounces ($0.17 per ounce)

6. BBQ sauce

The foundation of many a delicious meal (although here in NC this tomato-based concoction is not considered “real” BBQ sauce).

  • WINNER! Costco Sweet Baby Ray’s Barbecue Sauce, $5.49 for two 40-ounce bottles ($0.069 per ounce)
  • Amazon 365 Everyday Value Original Barbecue Sauce, $1.99 for 19.5 ounces ($0.10 per ounce)

7. Steak seasoning

The price difference here is pretty significant!

  • WINNER! Costco McCormick Grill Mates Montreal Steak Seasoning, $4.79 for 29 ounces ($0.165 per ounce)
  • Amazon McCormick Grill Mates Lower Sodium Montreal Steak Seasoning, $14.63 for 10 ounces ($1.46 per ounce)

8. Pickles

I didn’t find stand-alone relish at Costco (Amazon has it), but they both had some yummy-looking pickles.

  • WINNER! Costco Famous Dave’s Signature Spicy Pickle Chips, $5.59 for 64 ounces ($0.087 per ounce)
  • Amazon 365 Organic Kosher Dill Spears, $3.99 for 24 ounces ($0.17 per ounce)
(Image credit: Kelli Foster)


1. Potato chips

Potato chips are almost twice as much through Amazon!

  • WINNER! Costco Kirkland Signature Kettle Brand Krinkle Cut Sea Salt Potato Chips, $4.89 for 32 ounces ($0.153 per ounce)
  • Amazon Kettle Brand Krinkle Cut Sea Salt Potato Chips, $4.40 for 13 ounces ($0.34 per ounce)

2. Tortilla chips

Slightly cheaper at Costco, although you might like having that smaller bag from Amazon if you’re not planning a party.

  • WINNER! Costco Kirkland Signature Organic Tortilla Chips, $4.89 for 40 ounces ($0.122 per ounce)
  • Amazon 365 Everyday Value, White Corn Restaurant Style Tortilla Chips, $2.99 for 16 ounces ($0.186 per ounce)

3. Goldfish

Kids love goldfish crackers. But do you want your little ones eating 58 ounces of them?

  • WINNER! Costco Pepperidge Farms Goldfish Crackers, $8.29 for 58 ounces ($0.143 per ounce)
  • Amazon Pepperidge Farms Goldfish Crackers, $6.46 for 30 ounces ($0.22 per ounce)

4. Fruit cups

A good solution for picnic-packing, these are cheaper at Costco, and not an outrageously big quantity.

  • WINNER! Costco Dole Fruit Diced Peaches and Cherry Mixed Fruit Cups, $8.29 for 16 four-ounce cups ($0.13 per ounce)
  • Amazon Dole Fruit Diced Peaches, $2.50 for four four-ounce cups ($0.16 per ounce)
(Image credit: Emma Christensen)


1. Burger buns

Costco had two options for the same price, but they weren’t cheaper than Amazon. Amazon also had a ton of gluten-free options.

  • Costco Wonder Classic Hamburger Buns, $2.79 for two 12-packs ($0.116 per bun)
  • Costco Colonial Seeded Hamburger Buns, $2.79 for two 12-packs ($0.116 per bun)
  • WINNER! Amazon Hostess Hamburger Buns, $22.77 for four 8-packs ($.071 per bun)

2. Hot dog buns

When I searched, Amazon didn’t have any regular wheat hot dog buns available through Prime Pantry or with Prime free shipping — although a few companies offered free shipping separate from Prime. They had lots of gluten-free options, though. While they are more expensive than regular ones (of course), reviewers say they’re cheaper online than in grocery stores.

  • WINNER! Costco Wonder Classic Hot Dog Buns, $2 for two 12-packs ($0.083 per bun)
  • Amazon Ener-G Foods Tapioca Hot Dog Buns, $34.08 for six four-packs ($1.42 per bun)
(Image credit: Susanna Hopler)


1. LaCroix

These two are neck and neck here! Also, did you know that the tropical flavors like Coconut and Passion Fruit are more expensive at both places?

  • WINNER! Costco Lacroix Lime/Lemon/Grapefruit Variety Pack, $7.99 for case of 24 ($0.33 per can)
  • Amazon LaCroix Sparkling Water in Lemon, $4.77 for case of 12 ($0.40 per can)

2. Lemonade mix

Mmmmmm a cold glass of lemonade.

  • WINNER! Costco Country Time Lemonade, $5.99 for 82.5 ounces ($0.073 per ounce)
  • Amazon Country Time Lemonade, $6.99 for 82.5 ounces ($0.085 per ounce)

3. Mexican coke

Sweetened with real sugar, this stuff is great as is or as a mixer.

  • WINNER! Costco Coke of Mexico, $19.99 for 24 ($0.833 per bottle)
  • Amazon Mexican Coca Cola, $39.98 for 24 ($1.666 per bottle)

4. Bottles of water

Water is much more expensive through Amazon.

  • WINNER! Costco Kirkland Signature Purified Water, $2.99 for 40 1/2-liter bottles ($0.075 per bottle)
  • Amazon 365 Everyday Value, Spring Water Flat Cap, $2.49 for 12 1/2-liter bottles ($0.208 per bottle)
(Image credit: aradaphotography)

Entertaining items

1. Paper plates

The plates are more expensive on Amazon, but they had many more options in terms of package sizes and brands. Costco had about three.

  • WINNER! Costco Dixie Ultra MaxShield Plates, $15.99 for 186 10-inch plates ($0.086 per plate)
  • Amazon Dixie Dixie Ultra Heavy Duty Paper Plates, $18.99 for 176 10-inch plates ($0.108 per plate)

2. Paper towels

Amazon’s in-house brand is still more expensive than Cotsco’s own brand.

  • WINNER: Costco Kirkland Signature Create-a-Size Paper Towels: $15.69 for 12 rolls (1334.6 total square feet; $0.012 per square foot)
  • Amazon Presto! Flex-a-Size Paper Towels, $23.04 for 12 “huge” rolls (869 total square feet; $0.027 per square foot)

3. Paper napkins

Amazon napkins are cheaper!

  • Costco Kirkland Signature 1-ply napkins, $8.49 for 1,040 napkins ($0.008 per napkin)
  • WINNER! Amazon AmazonBasics 1-ply Beverage Napkins, $21.64 for eight packs of 500 ($0.005 per napkin)

4. Plastic cups

The signature red party cup is cheapest at … Costco!

  • WINNER! Costco Kirkland Signature Chinet The Big Red Cup, $9.99 for 240 18-ounce cups ($0.042 per cup)
  • Amazon Solo Red Squared Plastic Party Cups, $18.60 for 200 18-ounce cups ($0.093 per cup)

5. Charcoal

To fire up your grill.

  • WINNER! Costco Kingsford Professional Competition Briquettes, $13.99 for a 36-pound bag ($0.389 per pound)
  • Amazon Kingsford Original Charcoal Briquettes, $21.93 for two 7.7-pound bags ($1.424 per pound)

In conclusion: Costco is almost always cheaper, but Amazon usually has quite a few more options, and often they have promotions like getting $10 off if you spend more than $100 on Pantry items. Obviously, there’s a convenience to shopping and ordering online and having everything delivered straight to you — you’ll just have to deal with the built-in cost of having the stuff shipped out.