Our group has been running now for over twenty years, and I would never have considered asking anybody to chip in for materials. I make a practice of loaning out Player's Handbooks until a player decides they are going to stick with the group and buys their own. I also loan out the other books and gaming suppliments to new DM's. We've had over three dozen different players, and I have always gotten all of the materials back. Heck, I even had one player go out on his own and purchase me a new copy of Best of Dragon Vol. 2 after the one I loaned him got damaged.
On the other hand I expect all players to bring food and beverages for the group to share. We've had one mooch since day one, but since he's my kid brother I've let it ride.