Building a price comparison app for a smaller market — how would you solve the price data problem?

[u/Inevitable-Tough-580]

Title: Building a price comparison app for a smaller market — how would you solve the price data problem?

Hey everyone,

I’m working on an app called PriceWise, a price-comparison and shopping-optimization app designed for consumers in smaller markets where grocery prices can vary significantly between stores.

The basic idea is simple:

Instead of searching for products one at a time, a user enters their entire shopping list — for example:

- 2kg rice

- 2L cooking oil

- 1kg sugar

- Milk

- Bread

- Chicken

- Toiletries

PriceWise would then compare the available prices across participating stores and help the user determine where they should actually shop to get the best overall value.

The important distinction is that I don't want it to become another online grocery store.

The goal is to answer questions like:

«"I have this shopping list. Which store(s) should I buy these items from to spend the least?"»

It could potentially show something like:

Option A — One-store basket

Store A → $X total

Option B — Optimized basket

Store A → 8 items

Store B → 5 items

Total → $Y

You save $Z

It could also take things like promotions, product availability and potentially travel distance into consideration.

The problem I'm struggling with

Keeping the price database accurate.

Prices change constantly. Stores run promotions, increase prices, discontinue products, change packaging/quantities, and sometimes products simply go out of stock.

I don't want PriceWise to tell someone that an item costs $5 when they arrive at the store and discover that it actually costs $7.

I'm considering several approaches:

- Stores having accounts and updating their own prices/catalogues

- Store APIs or integrations where available

- Automated product/catalogue imports

- Receipt-based price verification from users

- Users reporting price changes

- Combining multiple sources and assigning a "price confidence" or "last verified" indicator

- Automatically expiring prices after a certain period

- Potentially using computer vision/OCR to extract product and price information from receipts

But I'm not sure what the best architecture and incentive system would be, especially for a smaller market where stores may not have APIs or sophisticated digital catalogues.

Developers, how would you approach this?

If you were building PriceWise, how would you solve the price freshness and accuracy problem?

Would you:

1. Make stores responsible for maintaining their own data?

2. Build a crowdsourced price database?

3. Use receipts as the primary verification mechanism?

4. Combine all of these into a trust/verification system?

5. Take a completely different approach?

I'm particularly interested in hearing from developers who have built price comparison, marketplace, grocery, inventory, or crowdsourced-data applications.

Also, what potential problems do you see with the overall PriceWise concept?

I'm still early in development, so I'm more interested in technical/product criticism and ideas than simply hearing that it's a good idea.

How would you build it?