Mercari.jp

I'm a frequent buyer on online sites, and Mercari.com has to be the worst one I've dealt with. Some reasons: 1) A seller can cancel your purchase without providing a reason with no opportunity to provide feedback by the buyer. 2) The transaction fees for the buyer are very high -- check them out before buying. 3) Customer service is terrible if you have a problem with a seller. Mercari protects bad sellers and provides little support to buyers.