You can get 1000' reels of Kodak Eastman Double-X 35mm movie film for $699. 1000', at 64.5"/36 exposure load yields 186 loads at $3.76 / load.
Arista EDU film is $52/100ft (100ft is a much easier amount to deal with) with 18 loads per roll the price is $2.89 / load.
You, of course, have to supply the labor, the empty cassettes and DX stickers (if needed).
There used to be (and maybe still are) firms that sold partial reels of cine film left over from movie shoots.
If you are using a Nikon F/F2 or a Leica Mx then you can use their infinitely re-loadable light-trap cassettes.