For a “basic smithy setup” all you really need is a roof and a dirt floor. Sand would be better than dirt, but dirt can get you started. All my forges have started as a patch of bare dirt in my backyard with a simple pole and tin roof frame around the patch. I eventually dig it up to a depth of two feet and fill it with sand. I’ve only done this twice. Once you have the sand, cover the sand when you don’t need it (to spill molten metal into) with 1/4 inch thick iron plates or steel plates. That keeps the sand where you want it.
For a “basic smithy setup” all you really need is a roof and a dirt floor. Sand would be better than dirt, but dirt can get you started. All my forges have started as a patch of bare dirt in my backyard with a simple pole and tin roof frame around the patch. I eventually dig it up to a depth of two feet and fill it with sand. I’ve only done this twice. Once you have the sand, cover the sand when you don’t need it (to spill molten metal into) with 1/4 inch thick iron plates or steel plates. That keeps the sand where you want it.