You can try this at Pro8
Dead Link Removed
which is 50' of Regular 8 white leader for $10.00 plus shipping.
I have never bought from them. I don't know if it is acetate or mylar (estar). If you are using film cement you will need acetate (mylar won't stick). I assume you don't have an ultrasonic film welder. However, splices work fine. If you have some spare lengths of film (discards, etc. you can remove the emulsion with chlorine bleach, wash well and get clear leader). If you have some unprocessed discard film you can develop it in the light for black leader. I have never seen academy leader in Regular 8, but it probably existed at some point. If you are not in a rush, (I am in the North of Canada) PM me and I'll send you 20' of white or clear or black gratis. It may take a bit to find. My store room was -38 yesterday.
Cheers,
Clarence