Pay for a download of the manual? Certainly not worth any more than keyclicks, bandwidth, drivespace, and time; its readilly available online for
free (both HTML and PDF) ... as are many declassified or never classified military publications. Looks to me the eBay vendor hawking this is just your typical opportunistic scam artist seeking to make a buck off the unwary.
Different story if it were a physical copy (a few bucks at most from just about any decent military surplus vendor - real common manual) - but it ain't, so it ain't.