It's not just coins, but that's where most of it goes (though it did have to cover the difference between the car I needed vs. the car I wanted...one is a requirement, the other is, well, fun money). As for the husband, that falls under 'what he doesn't know doesn't hurt him'. . Actually he has his own 'fun money' fund too. Seriously though, if it's expensive I'll tell him and let him know where the money came from. I try and keep him updated with our financials but he really hates listening. As long as we are overall responsible with investments, savings, etc. he is fine. He just gulps once in a while. I make him look at the net worth statement at the end of the year though.