Coins aren’t too hard to find, so don’t be afraid to spend them.  Although the price tag for the Master of Metal Bonus Card might seem steep at 75,000 Coins, the benefits can be life saving.  Once you play the card, 10% of Copper Coins get turned into Health Coins.  The bonus can be upgraded to a whopping 35%.

This translates into a small but steady stream of Health Coins that you can pick up while you run through a Floor.  This can work very well with the Mechanical Ticker’s Health regeneration to keep you topped up on Health or help you recover from damage while in the middle of a Floor.  Staying alive is worth the cost of a few Copper Coins.