A $1 billion idea...that I know I'm not ready for

This pretty much exists in at least Sweden. Check out http://www.prisjakt.nu/ ( translated to english http://translate.google.com/translate?sl=sv&tl=en&js... ). You said something like this would take 10 years to build and Prisjakt actually started 10 years ago. :-) They don't index everything of course but probably covers 99% of everything tech related and have been expanding in to new product segments all the time. Except the web site they of course do have phone apps which let you search for a product and then choose to display all the stores around you that carry that product and to what price and if they have it in stock. If you have a Swedish store selling anything online (or offline more and more) you "have" to exists on Prisjakt and have your full inventory with prices and stock status supplied to them. If you are among the cheapest stores on a popular product this of course will get you a lot of traffic. But there are more layers than just price indexing. They do have ratings and comments for all products and all stores. Myself personally would never buy anything from a store with bad reviews on Prisjakt, be it online or offline.

I would guess they started back in the days just scraping web sites on their own and then gradually got stores to supply them with "price files" that contained everything they needed. I know they have deals with create-your-own-web-shop businesses like Shopify and others so that these businesses create the price files automagically for every store THEY have.

As for revenue I believe that a store has to pay Prisjakt to actually have Prisjakt put up a clickable link to their web site. So if I search for Samsung Galaxy S III and go to the product page, I am presented with an array of stores carrying that phone, and I can click to go immediately to the stores own product page for Samsung Galaxy S III and go through with my purchase. If you don't pay it seems your website url is more hidden (on the store profile page) it's not clickable even their. You can also pay extra for having your logotype visible etc. They probably have a lot more going on as well.

2010 Prisjakt had $7.6M in revenue and made a $3.36M profit.

Jesse, your enthusiasm for looking at solving an obvious problem is admirable. I don't want to be one to burst your bubble, but there are a bunch of reasons why this hasn't happened so far. Unfortunately, your strategy of give-it-away is basically 'build-it-they-will-come', and access to solutions in this space hasn't been a problem.

If, after reading all the recommendations on here about how you'll fail, you still think this is worthwhile to approach -- spend your time understanding the retailer (not the consumer user.) If you can meet the retailer's needs, you're onto something.

Spoiler alert: be prepared to learn about how everyone else has tried and failed to do exactly what you're proposing.

Years ago a friend of mine worked at a local BestBuy-style retailer as a consultant. I asked him why they continued to use green screen POS terminals on the sales floor when much better technology existed. Apparently they had tried 3 separate attempts to implement new systems at costs of millions of dollars. These initiatives failed and even if they reached a pilot implementation stage, the company would roll back to the old trusted system with all its flaws. These systems often have extraordinarily complex and arcane integrations with multiple supplier and manufacturer systems to manage inventory and supply flows, calculate commission/spiffs and payroll, and integrate with ecommerce systems. IE, like any decently sized software project, the devil is in the integration, and the sales cycle is almost comically long.

Eliminating the licensing costs of a new untested inventory system is not a very compelling incentive for any medium-to-large sized retailer to consider trying out an untested startup's product. For various reasons the IT deparments of big retailers are very conservative.

As for smaller retailers and mom-and-pop-shops that have less integration concerns. It might be easier to have them find your system and be willing to invest hours of labour to have staff recode their existing inventories into your system and integrate this into with their existing POS systems (oops, there's that problem again) or I guess pay you for your fully-integrated POS system.... signing these up presents its own set of challenges. I think you're overestimating the licensing costs of existing POS systems for smaller retailers, and underestimating the costs of replacing any system that has already established itself.

A better approach might be to get a feeds of data from the inventory systems that already exist, which larger retailers are already sharing with their suppliers. Then you're still faced with similar integration problems, just from the other side. Others in this thread have covered the reasons why it would be very difficult to convince retailers to give up this valuable information.

So true.

The other significant thing here is just how fractured the retail POS market is. There are literally dozens of single-point POS systems, and Milo integrates with 5 of the larger ones. Many of them are regional players who built their market up through hands-on customer service. They just aren't going to get unseated that easily.

There are no billion dollar ideas. There's billion dollar executions.

Err, that sounds wrong... you get the idea!