By Darren · Published Nov 3, 2026 · Updated Nov 3, 2026
Looking for the lowest bulk peanut butter price per ounce? Unopened jars keep for months, and warehouse 2-packs cut the per-ounce price sharply. We compared Costco’s Kirkland Signature Organic, Sam’s Club’s Member’s Mark Natural and Jif Creamy by price per ounce, both before and after an estimated membership-fee share.
Price status:
- Member’s Mark Natural 2×40 oz, $7.78: Price checked Nov 3, 2026, 11:00 AM ET at Sam’s Club, online; may differ in-club and by region.
- Jif Creamy 2×48 oz, $11.98: Price checked Nov 3, 2026, 11:00 AM ET at Sam’s Club, online; may differ in-club and by region.
- Kirkland Organic 2×28 oz, $9.79 in-warehouse (Sterling, VA), per WarehouseHawk, viewed Nov 3, 2026. Not confirmed on Costco’s site. The tracker shows it up $2.00 since Aug 31.
What is the bulk peanut butter price per ounce?
Real Value Matrix
| # | Retailer | Price | Qty | Membership / buy | Cost per unit | vs. best |
|---|---|---|---|---|---|---|
| 1 | Sam’s Club (Member’s Mark Natural 2x40 oz) | $7.78 | 80 oz | — | $0.097/oz | Best |
| 2 | Sam’s Club (Jif Creamy 2x48 oz) | $11.98 | 96 oz | — | $0.125/oz | +28.3% |
| 3 | Costco (Kirkland Organic 2x28 oz, warehouse) | $9.79 | 56 oz | — | $0.175/oz | +79.8% |
Membership fees are spread across your purchases per year. Prices change often — confirm at the retailer.
| Product | Price | Oz | Per oz, without membership | Est. per oz, with membership share |
|---|---|---|---|---|
| Member’s Mark Natural 2×40 oz (Sam’s Club) | $7.78 | 80 | $0.097 | $0.160 (+$5.00) |
| Jif Creamy 2×48 oz (Sam’s Club) | $11.98 | 96 | $0.125 | $0.177 (+$5.00) |
| Kirkland Organic 2×28 oz (Costco warehouse) | $9.79 | 56 | $0.175 | $0.272 (+$5.42) |
Sam’s Club listed Jif at $11.98 on its product page when checked. The Costco warehouse price of $9.79 (Sterling, VA) is per WarehouseHawk, viewed Nov 3, 2026, not from Costco itself. The tracker shows it up $2.00 since Aug 31.
Jump to how we check prices for the membership-fee method.
What do you actually get for the money?
Member’s Mark Natural
The cheapest per ounce either way: about $0.10/oz before membership, about $0.16/oz with the estimated fee share. Sam’s Club describes it as no-stir natural peanut butter made with sea salt and cane sugar, with no high fructose corn syrup.
Jif Creamy
About 3 cents an ounce more than Member’s Mark before membership ($0.125 vs $0.097), and about 2 cents more with the fee share ($0.177 vs $0.160).
Kirkland Signature Organic
About 80% more per ounce than Member’s Mark before membership ($0.175 vs $0.097). You’re paying for organic ingredients, so it isn’t a like-for-like comparison. Check the label if you want a spread without added sugar.
Which peanut butter should you buy?
BUY: Member's Mark for value; Kirkland if you want organicMember’s Mark Natural is the best value with or without the membership share. Choose Kirkland Organic if you want organic. Don’t join a club just for peanut butter.
Is 80 oz too much for your household?
A household using about 6 oz a week gets through 80 oz in roughly 13 weeks. Check the best-by date before you buy and store unopened jars somewhere cool and dark.
Bulk Viability Check
Doing a big warehouse run anyway? See our Kirkland vs Charmin cost-per-sheet comparison.
How do we check prices?
We read each price on the retailer’s own product page where it loads, or from a named third-party tracker where it doesn’t (we say which in the notes). We divide the price by the pack quantity to get a cost per unit. For warehouse clubs we show two numbers: the shelf price alone, and an estimate that adds a share of the basic membership fee (Costco $65/yr, Sam’s Club $60/yr) charged in full to this one item. We spread the annual membership fee over an assumed 12 trips a year ($65 Costco = $5.42/trip; $60 Sam’s Club = $5.00/trip). If you already have a membership, use the first number.
Where do these prices come from?
- Sam’s Club: Member’s Mark Natural Creamy, 2 x 40 oz
- Sam’s Club: Jif Creamy, 2 x 48 oz
- WarehouseHawk: Kirkland Organic price tracker
Frequently asked questions
Is Member’s Mark peanut butter cheaper than Kirkland?
Yes. Member’s Mark Natural was about $0.10/oz (checked on Sam’s Club’s site) and Kirkland Organic (warehouse, tracker price) about $0.17/oz before membership; with an estimated membership share, about $0.16 vs $0.27.
Why is Kirkland peanut butter more expensive online?
Costco.com prices usually include delivery, so they run higher than warehouse prices. We couldn’t confirm a current Costco.com price, so we left it out.
Is a bulk 2-pack worth it for a small household?
Only if you’ll finish both jars before the best-by date.
About the author: Darren is the founder of Frugal Deals Hub. He compares prices at US warehouse clubs and retailers (Costco, Sam’s Club, Amazon, Walmart and Target) by cost per unit, using prices checked on each retailer’s own pages and dated on every post.