EBay, Collectors, Flea Market & Antiques

Very strict there. If you sell the same kind of item more than six times, you are considered a business, must register it, and be taxed as such. I don‘t know where the threshold between private sales and a business is in the USA, but in Germany, so many people were conducting thriving businesses on eBay right past the tax man that their finance authorities cracked down with the six-times-and-you‘re-a-business rule. Some still try to get away with it, but if you‘re caught, the fines can negate all previous profits.

Never forget: countries run by bureaucrats are always looking for ways to a) create more bureaucrats, and b) find ways to make an ever-shrinking public pay for them.