is used for poker. Many california card rooms and high-limit games are played with a collection (typically $5-$10 per half hour) rather than a rake (typically $4-$5 per pot).
An example of how this lammer/button is used: if you take a seat in a game that has no waiting list the house will often comp your first collection.
The dealer will give the player the free collection button so as to inform the next dealer, floorman, eye in the sky, etc. At collection time you just throw the button to the dealer in lieu of chips.
As a former craps dealer here in Las Vegas i have never seen a free collection button in use at a crap table.