it was their policy to do this its not so strange for a company to give free samples to interested users.
(i often give away things i sell, and i know companies have given me free things from film to lacquor plates. )
to be honest 100s of feet of film cost next to nothing to the manufacturer...
on the other hand, laquor plates, well they run about 20-30$ each (list price) you can see how they are made
at transco on "how its made " if you have netflix
... kodak mailed thousands of rolls of portra a few years ago ... it was kind of funny ...
a little roll of 35mm in a big tube with a wraparound ad on it, talk about advertising, and overkill ..
in the end a company just wants constant-consumers, and if giving them a "taste" gets them to buy a few more at the normal price it did the trick ... and its good PR to give stuff away. even 5-6 years later people are still talking about it!