Shinjuku
Cheap film at Kitamura camera, West Exit of Shinjuku station (and across from the burger king). 178 yen a roll (about $2.00 US) isn’t bad, but it used to be 100 yen a roll a year or two ago.
This Kitamura shop has a good used equipment selection up on the 4th floor. The bigger shop is in Akihabara across the street north of the Yodobashi Camera there.