[1] https://en.wikipedia.org/wiki/Use_taxAh, if only. I swear, sometimes it seems like Amazon knocks 10% off MSRP, while Radio Shack adds 10%. And I'm talking sticker, not sales tax.
But, I do believe that convenience of easy ordering (for lazy ppl like me), is bigger differentiator than a couple of percentage points on pricing.
Infrared LED at Radio Shack? They wanted something like $6 per LED. You'll find the same part online for pennies.
1) Store building rent (they ship directly from their warehouses)
2) Cashiers / sales salaries
3) Store security, cameras, loss prevention.
4) Store utilities and other - electricity, water, insurance, heating, cooling, inspections.
5) Liability (such as customers falling or pretending to fall)
6) Inventory tracking, moving things around shelves, optimizing, etc.
Also the convenience that the parent talks about is not what I'd call convenient. Basically the last 4 times I went to a store, they didn't have the thing I wanted, or it was out of stock. And most of the time I want to go to a store, it's not open.
I assume this is at least partially cancelled out by not having to deliver items to stores.