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—such wholesale business is traditionally tax exempt though forms need to be filed, and a certain number of hoops jumped through. Still, should this new legislation pass (and if it doesn't, something similar to it will pass soon), larger stamp dealers will be at a disadvantage to smaller ones. Most of the problem with charging sales tax relates to the fact that collectors are not used to paying it and will be irritated by it. For the vast majority of purchases, the tax is effectively meaningless. If a set of Zeppelins is worth $1000 to you, and you can afford it, then the new price of $1050 (stamps plus sales tax) won't make a difference to most buyers. The effect is psychological. No one likes paying a tax when they didn't have pay one before. The experience of the German stamp business, when their national sales tax (actually a value added tax) came in thirty years ago, is instructive. The tax was far more onerous than any state sales tax—it was 18%.  Business spiked in the months preceding the imposition of the tax as collectors with disposable funds bought stamps before the tax took effect to take advantage of the lower price. Then, after the tax was imposed, business slipped for several months. Now, almost no one remembers the way it was, and all pay the tax as part of the purchase price as they do with all the other things that they buy.