Spent last week in Tokyo. I wanted to go to Jimbocho where I heard there are a lot of old book stores and antique shops, but I didn't have a chance to go to that area. There was just too much other stuff to see, and unfortunately this wasn't a postcard buying trip. I did find a few tourist shops selling modern postcards though: Most of the modern cards I found were selling for around 80 Yen - around 75 cents. Lots of nice wood block prints, printed on nice paper. Much nicer than typical glossy, scenic cards found in the US (although there were plenty of views of Tokyo to be found as well).