For a 5cm diameter coin, metal print costs, one-offs (material cost):

Stainless Steel - USD$44
Gold Steel - USD$48
Brass - USD$191
Stainless, Gold Plated, 14k - USD$225
Pure Silver - USD$317

And then Gold and Platinum dust prices are just insane. Titanium is out of stock for the printer model...

Printing is thus prohibitively expensive.

Some fun things we can print though:

Sandstone - USD$8
100% Pure Platinum - USD$13,252 (dies)

If the plan is to make metal coins in large volumes, you'll want to get a third party to make a die or a stamp.