In Japan, Yahoo Auctions is still going strong. It's a great place to find car parts. Related but I guess targeted at the anglosphere:
http://jp-carparts.com has schematica of cars so that you can find pretty much any part you need.
https://www.amayama.com is a place you can put the part number in and actually order the part directly from a bunch of Japanese suppliers.
You want some of those little plastic interior clips for a 1996 Nissan? They have them. Power steering pump? Entire transmission? Window glass? Hood latch?
It is often cheaper than getting it locally too because the local markets assume scarcity and Japan tends to not price gouge in the first place.
http://jp-carparts.com has schematica of cars so that you can find pretty much any part you need.
https://www.amayama.com is a place you can put the part number in and actually order the part directly from a bunch of Japanese suppliers.
You want some of those little plastic interior clips for a 1996 Nissan? They have them. Power steering pump? Entire transmission? Window glass? Hood latch?
It is often cheaper than getting it locally too because the local markets assume scarcity and Japan tends to not price gouge in the first place.