I wanted to add one other thought. The reason mom and pop shops went away is because these soulless giants could offer prices mom and pop couldn't compete with. If you compare Swappa to Ebay it's the reverse, here. The mom and pop (Swappa) is able to offer the service and little things the giant ebay can't and Swappa can do it for less.
If mom and pops were able to accomplish what Swappa has there would be no Walmart.