I've found that the best place to buy tsums online is either through social media like Tumblr or Instagram or through Amazon. And if you buy through Amazon, there are a few details you should check for to make sure you're getting a genuine tsum: Shipping location is a big one, if it's shipping from somewhere in Asia outside Japan or maybe Hong Kong, it's probably fake. Along that note you also want to make sure the item description says "US Disney Store official" or "JP Disney Store official" or "EU Disney Store official" depending on where the tsum you want is currently available. Shipping location should match that statement to be even more sure. If the item description says "new with tags" or "nwt" that's also good, but "nwt" on its own isn't enough anymore since tags can be faked. If you buy a tsum on Amazon that fits all these criteria, and then end up with a fake, you can at least report the seller for fraud since they specifically stated that they were selling an official Disney Store or Disney Park tsum.