You might also try Specialized products where I got mine. Granted the sheets are 9 X 6.5 which I cut into roughly 3 X 9 strips. At basically .25 cents a strip ( .50 a sheet) I didn't think it was out of line. A pack of 25 goes for $11.25.
The carry a decent selection of 15,12,9,5,3,2,1 and .3 micron. All sold in 25 packs for the same $11.25.
I am waiting on a delivery of the same films. Bought 5,3 and 1um and plan to cut them in half. That right there should last quite some time as I also still am using my regular hones.