Mail and Internet sales have long had an advantage relative to ordinary retail sales in that there was no sales tax charged for interstate sales. Buy a set of zeppelins from your local retailer for a thousand dollars, and it will cost you $60-$80 more than if you you buy them online. This is one of the reasons that there are so few stamp retailers anymore with shops. Because of the sales tax exemption on interstate retail sales nearly all stamp sales take place tax exempt through mail order and the internet. Even most sales that take place at stamp shows are effectively tax exempt as the smaller dealers who have booths at these shows rarely charge tax. This is all about to change.
Retail stores have long complained that this system is unfair (and it is). Larger retailers, who maintain retail outlets at most of the hundreds of malls throughout the country are at a distinct disadvantage to the single venue mail order houses. If you buy a spatula from a mail order catalog from Williams-Sonoma, you most likely will be charged sales tax as Williams-Sonoma probably has a physical location near you. Buy the same spatula from Amazon, and it's tax free. This kind of inequality in the tax code is what most people think is unfair and should be changed, though these tax breaks have largely been sacrosanct because they benefited so many buyers, and, most significantly, until recently, the largest retailers, such as Amazon, were behind it. But Amazon has opened fulfillment centers in many states to get orders to buyers more quickly and so now needs to charge tax on many of its sales. Accordingly, its enthusiasm for the current system has waned. Further, collecting and paying sales tax from the hundreds of different local entities, all of which have different rates and products that are exempt, will prove a great new growth business for Amazon which plans to sell to small retailers its tax fulfillment services (they collect and remit the tax for you, and you pay them a fee).
There is no doubt that the stamp business has benefited from being sales tax free. Current proposals before Congress call for exemptions from collecting and remitting sales tax for business that sell less than $1 million per year, which should exempt all but the largest stamp sellers. And most larger stamp dealers do much of their business to other dealers