Just a clarification: Tradesy isn't charging tax. They are collecting it because your state demanded it and they're forwarding the taxes to your state. (Amazon and ebay have been collecting sales tax on my purchases for well over a year because my state was one of the first to get smart and demand it.Then I got their email that they are now charging tax. I figure people got their orders in before this change. Too bad, I think the sales tax issue brought a lot of traffic for individual resellers. CA sales tax is 10%, so buying off Tradesy was a 10% discount on tax alone last year.
Although all states with sales tax have a line on their state tax return that requires us to pay taxes on out of state or online purchases, few people were doing it. So now, we can't cheat on our taxes.
(My state also requires Paypal to send a 1099 for ALL payments received regardless of the number of transaction or the total dollar amount. So every cent has to be claims on my taxes.)