There are a lot of nuance to setting price. I’ll just touch on the basic difference between Japanese pricing, and pricing common in western countries. Simply, if you want to set a .95 or .99 price, do 80 for japan. So $19.95 or $19.99 would be 1,980 yen (ignoring exchange rates here). This may seem strange to westerners, but the price perception is very different in Japan. You will probably see lots of pricing like this if you browse Japanese ecommerce sites.
There are lots of other effective price points, and we can dig into those later. Maybe there will be different ones that are more effective for Amazon in particular. Constant price testing at the beginning will give you some good info.
*This post originated from a post in the Amazon Japan Facebook group, “Amazon Japan PL”. The information may well have changed by the time you read this. Please check the DATE of the post before you make any decisions based on this information!