Mike Krahulik once ran a game on stage at PAX where he unveiled envelopes which represented locked chests. He then told the group there was another set of envelopes, each of which cost $5 for any party member.
He effectively introduced paid loot boxes to tabletop gaming.
I don't know if it's the type you're looking for but I'm quite happy with my Genki Covert Dock. It does the job quite well, and the portability is nice to have.
Let's not even talk about zinc.