Can the app fetch supermarket prices automatically?

Not reliably, and not without legal risk. Supermarket sites do not offer open price APIs, scraping them breaks their terms and breaks whenever they redesign, and coverage varies wildly by country. Manual logging while you are already standing at the shelf takes about ten seconds and is what makes the app work anywhere.

How do I stop the item list becoming a mess of near-duplicates?

Fuzzy-match on the item name when logging and offer the closest existing item before creating a new one. "Milk 2L", "milk 2 l" and "Milk (2L)" as three separate items is the failure mode that kills this app in week two, and a match prompt at entry time is far easier than a merge tool later.

How to Build a Grocery Price Tracker App with AI (2026)

What a grocery price tracker app needs

Log a price for an item at a store, with size and unit
Automatic unit price so different pack sizes compare honestly
Price history per item with the lowest ever seen
Basket view — which store is cheapest for this week's list
Alert when a logged price is well below that item's average

The screens

Screen	What it does
Items	Tracked items with latest price and cheapest store
Log Price	Item, store, price, pack size — unit price computed live
Item Detail	Price history chart by store, best price ever
Basket	This week's list totalled per store, cheapest highlighted
Stores	Stores you shop, with how often each wins on price

The data model

Item: name, category, defaultUnit (g | ml | each)
Store: name, location
PriceEntry: itemId, storeId, price, packSize, unit, unitPrice, observedAt
BasketLine: itemId, quantity, addedAt

The build prompt (copy this)

Paste this into ShipNative and it becomes a working React Native app with these screens, navigable in a live preview, in about two minutes:

“A grocery price tracker. Users log what an item cost at a store along with its pack size and unit, and the app computes and stores the unit price so a 400g and a 750g jar can be compared honestly. Each item has a detail screen with a price history chart, one line per store, and the lowest unit price ever recorded. A Basket screen holds this week's shopping list and totals it against the most recent known price at each store, highlighting which single store is cheapest for the whole basket and which items are notably cheaper elsewhere. When a newly logged price is more than 15% below that item's rolling average, show it as a good buy. Screens: Items, Log Price, Item Detail, Basket, Stores. Everything is stored on the device and works offline, since supermarkets have terrible signal.”

Then iterate with small, screen-specific prompts (“make the primary button bigger”, “add an empty state”), preview on your own phone, and export the full Expo project whenever you want. The full method: how to build an app with AI.

How it makes money

Hard to charge for directly — this is a save-money app, and asking a price-sensitive user for a subscription is a difficult sell. The realistic paths are a one-time unlock of about $5 for unlimited tracked items, or keeping it free as a portfolio and audience-building app. Do not build this expecting subscription revenue.

Implementation and the revenue math for every model: how to make money from an app. When you’re ready to ship: App Store and Google Play publishing guides.

Build it now

The prompt above is free to run at shipnative.dev — working grocery price tracker app on your phone today, full code export, no credit card.

How to Build a Grocery Price Tracker App with AI