One thing to think about is, as a brick and mortar store, you might not want to move all your products from your inventory storage of 15 years, over to a new inventory system. Free or not, it's a PITA. It's especially painful if you're the store with the higher product pricing.

Another thing to consider is, many people shop by convenience, not by price. I always pay for convenience. Not worth it to drive 5 miles out of my way to save $1.

Not to say the idea couldn't work, and most startups are 3-4 years in the making before most people even hear about them.