Double-X 100' rolls Special Order??
If anyone is in a university program that has an eduction discount with Kodak you can get something like 30% off the motion picture films which XX stock is. That is the cheapest film you can get probably anywhere if spooling down from 1000ft rolls. Unfortunately I didn't know this when I was in school.
I'm shooting down my own 1000ft roll now over the course of two years. It's nice but after while you want to shoot something else. I shoot it at 200 or under, others on rff have pushed it pretty high. It is labeled for 200-250 indoor outdoor.