This web tutorial shows how to cast metal into shapes at home on the cheap.
It shows how to make your own greensand for casting out of 9 parts fine sand and 1 part ground up bentonite clay (clumping cat litter) by volume. Then slowly add water and stir just until it sticks together when you squeeze it.
The rest of it if you keep clicking for the next thing, shows how to make a drag out of a wooden box (a drag is a 2-part box that holds the clay for the 2-part mold), how to press an item into it and add a sprue (channel for casting) made from a dowel or section of old plumbing pipe, what to use as a parting compound (diatomaceous earth), how to make a charcoal furnace from old steel food cans and a scavenged dryer fan, also the crucible can be an old steel can - and a little about safety (plywood splatter guard!) You will also need tongs. I'm sure you can mock up a pair of tongs. A leather apron and welder's gloves and some goggles might also be good to have.
With this super-cheap setup, you could cast metals that melt at lower temperatures than steel into small useful shapes or ingots, without having to buy equipment from a casting supply house. Might be useful for post-SHTF, making metal items from scrap aluminum, copper or brass, or other similar projects. Maybe you could even cast your own bullets, although you shouldn't breathe lead fumes. But you'd be doing this outdoors, probably.
The equipment I saw for casting jewelry from a casting supply house got expensive fast, so this would be a way around that. I might still get the ceramic crucible, if I was dealing with precious metals. You'd want a different one for each metal. Also this greensand might not be the most detailed for fine jewelry. You might need to use something finer for the sand part, or experiment with just using the cat litter by itself. However, you would be able to cast tools, hardware, or rough, rustic looking jewelry with this particular recipe for greensand.