Costco doesn't require a membership to shop online, but a membership is necessary to access two-day delivery. The homepage of the website is very busy.
Jet's website is less busy, and free two-day delivery is advertised on all orders of $35 or more.
Costco's category page is also very busy. The large number of categories makes it more difficult to find things.
Jet's website is more straightforward.
Shopping for groceries at Costco seems to be less expensive, though you need to have a membership in order to access two-day or same-day delivery. At Costco, a pack of two 48 oz. jars of peanut butter costs $11.49. A single 80 oz. jar costs $12.99 at Jet. Costco offers a larger quantity for less money.
At Jet, about one liter of olive oil from Jet's Uniquely J brand costs $13.83. But a two-liter bottle from Costco's Kirkland Signature label costs only $3 more.
A 12-count box of Clif Bars costs $13.99 at Costco and $12.49 at Jet. In this case, Jet is the winner.
Jet offers 20-count packages of Famous Amos cookies for $6.70 each. If you were getting two, it would total $13.44 before shipping and tax. Costco offers a 42-count package for $14.49. Because it's only a dollar more for a few extra bags, Costco offers the better deal.
Costco sells a 24-count pack of Viva paper towels for $34.99. Jet sells a 12-count pack for $12.38. Buying two 12-count packs from Jet is less expensive than buying a 24-count pack from Costco.
Jet offers a four-pack of Clorox disinfecting wipes for $14.52. Costco offers a five-pack for $16.49. Costco's pack comes with almost 80 extra wipes for just a few dollars more.
Some products cost almost the same on each site. A 55" VIZIO 55 Inch 4K Smart TV is $598 at Jet and $599 at Costco.
Many medicines cost less at Costco. A 200-count bottle of Advil Liqui-gels is $19.99 at Costco and $21.49 at Jet.
Even though Jet's website is a bit easier to use and offers free two-day delivery without any membership fees, Costco ultimately offers better deals across the categories we examined. Even though Costco requires a $60 annual fee to make the most of its deals, it has lower prices than Jet.