Price comparison for groceries on your real shopping list
Grocery prices vary more between stores than most people think, but nobody has time to check five websites every week. Give your todo.is agent your usual list and the stores you can reach. It looks up online prices, compares by unit price, and says whether one store or a split trip saves more.
The prompt
- Do a price comparison for groceries for my shopping list: [MY SHOPPING LIST]. Compare these stores near [MY AREA]: [STORES]. Use each store's website or online shop, compare by unit price (per kg, liter or item), and allow equivalent store-brand products unless I marked an item "brand only". Note this week's promotions and multi-buy deals. Give me an Excel table (item, size, price and unit price at each store, cheapest store) and a short summary: the total at each store, the cheapest single store, and whether splitting between two stores saves more than [MINIMUM SAVING] after [EXTRA TRIP NOTE]. Mark items you couldn't find online. Then, every [DAY AND TIME], repeat the check for my list and send me the summary on WhatsApp.
What to change
- [MY SHOPPING LIST]: Items with sizes, e.g. "2L semi-skimmed milk, 1kg oats, 6 eggs, chicken thighs 1kg, olive oil 1L (brand only: Bertolli)". Or attach a photo of your list.
- [MY AREA]: Your town or postcode, so prices and stores match your region.
- [STORES]: 2–5 supermarkets you can actually reach, e.g. "Tesco, Aldi, Sainsbury's" or "Walmart, Kroger, Aldi".
- [MINIMUM SAVING]: Below this, one store is easier, e.g. "£8" or "$10".
- [EXTRA TRIP NOTE]: What a second stop costs you, e.g. "a 15-minute drive" or "a bus fare of $2.75".
- [DAY AND TIME]: E.g. "Friday at 17:00", the day before you usually shop. Each run uses a few AI credits.
Example result
- Grocery price comparison, week of October 12
- 18 items · 3 stores · prices from each store's website on Friday 17:00 · example figures
- Totals
- • Store A (big supermarket): £74.20
- • Store B (discounter): £61.40, cheapest single store
- • Store C (supermarket with loyalty prices): £68.90, or £63.10 with the loyalty card
- Best split
- Buy staples at Store B and these 4 items at Store C with the loyalty card:
- • Olive oil 1L, brand only: £4.50 vs £8.25 at Store B
- • Coffee beans 1kg: £9.00 (multi-buy deal) vs £12.40
- • Chicken thighs 1kg: £4.20 vs £5.10
- • Greek yogurt 1kg: £1.35 vs £3.10
- Split total: £51.60, saving £9.80 vs Store B alone. That's above your £8 minimum, so the second stop is worth it this week.
- Unit price traps found
- • Oats: the 500g pack at Store A is cheaper per pack but costs £2.10/kg more than the 1kg pack
- • Eggs: "value" 15-pack at Store B works out 4p per egg cheaper than the 6-pack deal
- Couldn't check online
- • Fresh bread from the bakery counter and loose bananas at Store B: priced in store only
- Next week
- The same check runs Friday at 17:00 and the summary comes to WhatsApp, with what changed since this week.
How to do it with todo.is
- Copy the prompt and write your usual list with sizes, your area and the stores near you.
- Paste it on the Today screen in todo.is, or send it to your agent with a photo of your list.
- Your agent checks each store's website and sends an Excel comparison with a clear answer.
- It repeats every week. Reply "add nappies size 4" or "drop Store A" to change the list.
Tips for a better result
- Always compare unit prices. Bigger packs aren't always cheaper, and promotions often hide in odd sizes.
- Allow store brands for basics like flour, rice, tinned tomatoes and cleaning products. That's where most of the saving is.
- Include loyalty-card prices only if you actually have the card.
- Online prices sometimes differ from shelf prices. Use the comparison to choose a store, not as an exact receipt.
price comparison for groceries: FAQ
- Which stores can it compare? Any store that shows prices on its website or online shop for your area. Stores that only price in store can't be checked, and your agent tells you which items it couldn't find.
- Can it order the groceries for me? No. It compares prices and gives you links. You place the order or go to the store yourself.
- Is it worth shopping at two stores? Only if the saving beats the extra time and travel. That's why the prompt asks for your minimum saving, so the answer is a clear yes or no each week.
JavaScript is required to use the todo.is app.