Right now, Widget Supply has a 3-groove ingot mold for just $8.97.
An ingot mold is used to cast strips of silver or gold so that they can be further reduced into strip or wire in the rolling mill. It’s a useful way to use up scrap as well as make special sizes of sheet metal for custom work, reducing inventory, or emergencies. The silver or gold is melted and poured into the desired groove and allowed to solidify.
3 Groove Ingot Mold [widgetsupply.com]