Back in grade school, this used to crop up from time to time — the GMs I knew (myself included) spent a lot more than their players did on games that the whole group enjoyed, so why not pool funds to buy books?
I never felt quite right asking my players to do that, and I don’t remember ever paying for the GM’s books myself as a player, either. And as we all got older, of course, spending money became less of a concern.
The truism that in any given group, the GM will be the one who owns the most books for the current game still seems to hold true, though. And when that’s me, I don’t mind.
So how about it — has this ever been brought up in your group? Did it come up when you were younger? I know of groups that have pooled their cash for digital projectors, but does anyone actually do this for books, adventures and the like?