Cash Deposit Boxes

I’ve been looking for a good cash deposit box lately. I’ve gone to the usual stores like Staples, Office Depot, Office Max, etc, but I’m not seeing exactly what I’m looking for. They have these plastic looking things with more slots for change than for bills. I’ve also seen some heavy duty fire proof ones from Brinks Security.

It’s just that I’m not really looking for a cash register, I just want a box with some slots for bills, to facilitate keeping track of my savings. Of course something with a bit of security would be nice. Maybe something with a security code in it, something fireproof, something heavy, and small enough to fit in a wall or something.
Perhaps the problem is I’m not sure I myself know what I want. What I do know is that I’ll know it when I see it.