A real challenge for traditional retail operations is the implementation of e-commerce into their existing business model.  It's not just as simple as Just Do It.  Nope, selling inventory online, in real-time, while running a cash register that sells from the same inventory as the online store is no easy task.  Your online store needs the integration of a barcode scanner or your cash register needs to allow for user mouse clicks and phone taps to make purchases simultaneously.  The problem is that most P.O.S. service systems are cloud based and not web based;  I have yet to find a 3rd party P.O.S. service that offered web hosting services and e-commerce functionality as part of their programs.  Amazon doesn't do social media and facecrook doesn't do e-comm, (they do marketplace, kinda like craigslist.org),,,  Did you ever wonder why that is.  
  The local beach liquor store ran into the problem above when considering the many different ways they could implement some sort of delivery or curb side pick up service.  They needed to allow customers the ability to purchase products online and track the outbound/ incoming inventory online with the integration of a barcode scanner.  Unfortunately, their current P.O.S. service provider has no way to offer or integrate e-commerce into their existing platform.  
  Soooo,,,  I think I've got a way to implement a barcode scanner via the Concrete5 community store.  This is what I'm working on now.  Whilst doing all of that, I did some background work on QR Codes.  I made the following contact form just for fun.  Use your QR Code scanner to see the contact info.  

F.Y.I.,,,  The above design idea was mine and not suggested by anyone;  It was generated via https://www.qrcode-monkey.com/
  It's a truckers mud flap for a QR Code if you didn't already know 

The following is an excellent video on UPC barcodes.