A Chittenden Trust Company Replica Bank Building Coin Bank with Key.   I would consider the condition to be excellent for a vintage piece .  I haven't cleaned it as I don't want to negatively influence the patina in any way and I am not familiar with how to do so professionally. 

I did read that the Chittenden is now People's United Bank and that the Bank is still standing in Burlington, Vermont. 

I wonder if it might be copper on brass  or heavy copper as a magnet would not stick.  I don't know, maybe you do.  The key is shown in the pics in the lock on the bottom.  It says Banthrico, Inc Chicago USA

It measures approximately 4 3/4" x 3" x 2 7/8 ".

If you google Banthrico Chittenden Trust Co, you will find a couple of listings.  One is an auction site and the starting price is $80 with the estimate $150-200.

Good Deal!!!  This Could Be Yours!