if in 1880 or later then buy a copy of birth c.s from General registry (they will search for you at a fee!) - there is also a list of researchers available via Manx museum who will do search for you but again at some cost.
I have been told that LDS will hire films to bona fide Family History Socs if they have no FHC nearby - if this is so then why not found a local FHS and hire in your own (only a suggestion).
The ManxMuseum (MNH) (who own copyright it seems on these films) will also agree to LDS selling copies but this generally is only to academic institutions and never to private individuals (I'm not sure if any have been released this way but I was informed that it was possible but applications were slow and tedious involving application to SLC then to MNH and then back to SLC)