Make a Costco weekly grocery list for under $100 with ChatGPT (real prices came to $167)

Posted

Mar 8, 2026 by Kathryn Jackson (GOBankingRates)

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Last checked

Oct 17, 2026

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Method:

How we verify

Evidence: Article or interviewA newsletter, journalist or interview account of what happened.

Outcome

GOBankingRates' Kathryn Jackson asked ChatGPT for a full Costco shopping list for the week under $100; it said the list was for a family of two and totalled $95. On Costco's website the same groceries came to $167, some items only came in larger quantities, and the list left out dairy like milk and cheese, tomatoes, other green vegetables, potatoes and other meats.

Agent

ChatGPT

The source didn't share its exact prompt, so we wrote this from what it describes.

Run this task now, exactly as written below. Everything you need is here, so start straight away and only stop if something required is missing or a rule below tells you to.

Goal: Build a week's grocery list for a specific store that really comes in under my budget at that store's current prices.

Fill in before running:
- Store: [e.g. Costco]
- Budget for the week: [AMOUNT]
- Household size: [NUMBER]
- Must-include basics: [milk, vegetables, etc.]
- Membership or delivery fees to include: [YES/NO]

Rules:
- Use the store's current online prices and pack sizes, and link each item.
- If an item only comes in a bulk size, say so and adjust the plan.
- Cover the basics I listed, including dairy and vegetables.
- Show the real total; if it's over budget, say so and suggest swaps.
- If a site asks for a login, a CAPTCHA or payment details, stop and hand control back to me.
- Ask for my OK before you pay, book, send, submit or cancel anything.
- Check facts that can change (prices, opening hours, dates, availability, rules) against the official source, and tell me anything you couldn't verify.

Output: A table of items with pack size, price and link, and an honest total.

You'll know it worked when: the total matches the store's website and covers a full week of meals.

Run this task now, exactly as written below. Everything you need is here, so start straight away and only stop if something required is missing or a rule below tells you to.

Goal: Build a week's grocery list for a specific store that really comes in under my budget at that store's current prices.

Fill in before running:
- Store: [e.g. Costco]
- Budget for the week: [AMOUNT]
- Household size: [NUMBER]
- Must-include basics: [milk, vegetables, etc.]
- Membership or delivery fees to include: [YES/NO]

Rules:
- Use the store's current online prices and pack sizes, and link each item.
- If an item only comes in a bulk size, say so and adjust the plan.
- Cover the basics I listed, including dairy and vegetables.
- Show the real total; if it's over budget, say so and suggest swaps.
- If a site asks for a login, a CAPTCHA or payment details, stop and hand control back to me.
- Ask for my OK before you pay, book, send, submit or cancel anything.
- Check facts that can change (prices, opening hours, dates, availability, rules) against the official source, and tell me anything you couldn't verify.
- Before finishing, re-add every price from the store page and compare your total with my budget.

Output: A table of items with pack size, price and link, and an honest total.

You'll know it worked when: the total matches the store's website and covers a full week of meals.

Before you finish: re-read my goal and constraints, check your answer against each one, and list anything you assumed or couldn't confirm.

Source

https://www.gobankingrates.com/saving-money/food/i-asked-chatgpt-to-make-me-a-costco-weekly-grocery-shopping-list-for-under-100/