New lens/camera prices are as high or higher then US mail order prices. Its really hard to beat B&H, Adorama, or KEH for new Nikon prices. HOWEVER.....

Used lens prices in Japan are great and the equipment is indistinguishable from brand new equipment. The Japanese take care of their equipment, and upgrade frequently, thus resulting in some good used lens prices. When the exchange rate was 120 yen/dollar I purchased a 80-200/2.8 2-ring for 580 dollars that looked like it had been taken out of the box and just put on display.

My favorite place for used lens shopping is Fujiya camera located in Nakano, about 30 minutes via train from Ginza. Its located just north of Nakano station on the we4stern side of town, outside the Yamanote line.

The prices are great at Fujiya, and the selection is among the best in Tokyo for both new and used equipment. They have shelves full of used Nikon (more popular here then Canon) and they will let you examine the lens fully to include providing a camera body to go through all the functions of the lens. They provide a (7 day I think) exchange policy and provide a Nikon International warranty if the lens is new enough to be covered. Fujiya camera also has some english speaking workers who can help you with the transaction. Overall its a bit out of the way and hard to find for westerners, but they must be doing something right because everytime I have gone I have seen westerners selling their used equipment and buying new stuff. Oh, that's right, they also offer good prices for your used equipment!