Just came across this news story... apparently GW is actually giving things away to gain market share. In Japan pdf's of the Codex books can be downloaded for free (some, mostly fantasy). I don't know how long this practice has been going on, but hopefully it works there and they think about doing it for some of the english language ones.
In browsing the site (via google translate) it looks like some of the updates and campaign books are free kind of like how GW used to do this for old WD articles.
Check it out here (you may have to change the country to Japan):
This story was found here: