The selling of used products in Japan is a HUGE business, far more than anywhere else in the world that I have seen. There are secondhand shops for everything imaginable. With so much competition, and the Japanese desire for products in the best condition, the shops are very conscientious about how they rank their products. There are also strict laws about how used products can be indentified, and sold. You will see many, many watches advertised as "used" when they are obviously new and unworn, with plastic still on bracelets, etc. This is due to the fact that unless the watch has been sourced from a certified original supplier, it cannot be sold as new. For anything in less than perfect condition, the market prices it significantly lower, and these products are often a very difficult sale. The catch all term that the Japanese use is "Junk" goods. If you are ever searching and come across this term, you need to be careful. In some instances, the products are broken and do not work properly, but, they might also classify something as junk, just because of a scratch or something that is easily rectified. One example might be something like a used laptop. If it is missing one key, it would be classified as "Junk" goods. It could be absolutely brand new in every other way, but because it is missing one key, it will be heavily discounted, and sold as "Junk" with no warranty or returns possible.
While on the subject, I might as well add a bit more colour on warranty, and returns. In America, it seems everyone is spoiled beyond belief with the ability to return goods, free of charge, and often after an extended period of time. In Japan, that concept is pretty much non-existant. Purchases of any goods, new or used, are considered final sale, with no returns possible. For new goods, any problems, even something that is broken right out of the box, will need to be handled by the manufacturer, the shop will not get involved. For used goods, the shop will usually offer its own warranty, but before the purchase is completed, the shop will ask you to inspect the goods carefully, for any problems or defects. Once you have confirmed all is okay, and the sale is complete, you cannot return the goods for any reason. I think this is one reason there have been many comments about how uncooperative shops are in dealing with overseas customers, and the entire transaction. It is just such a giant hassle for the shops, trying to communicate in a foreign language, accept payment, ship goods overseas (which is getting extremely difficult due to all of the regulations with CITES, as well as restrictions on batteries through the mail) and then handle a customer who expects a free return for some (to the Japanese) inane reason.The same goes for some of the angst expressed from people who did not get tax deducted from a purchase. Many of these second hand shops do not deal in tax free/duty free so they are not being uncooperative, they simply do not have the mechanism in place to handle it. There are still many large retail chains, that do not process transactions duty free, although it is becoming pretty common. I can even say that accepting credit cards, is a fairly recent development. Japan is still very much a cash and carry society, and I am not talking small. Even in 2019, it is not uncommon to see people pay cash for $50,000~$100,000 transactions such as luxury goods, cars, etc. Cash machines here used to have no limits on withdrawals, and even today, the standard withdrawal is capped at ~$10,000 a day. No, that is not a typo!
As far as negotiation, it is generally a no go, but depending on the shop, as a foreigner, they might be willing to consider a slight discount.
Happy to answer any other questions you guys may have.