I built my own foundry last year for melting aluminum. Here's the parts list:

Steel bucket (5gal)
2x buckets firebrick mortar
12" piece of steel pipe
PVC butt joint
PVC pipe
2x U-bolts
A wide mouth bucket for molding the lid
A section of rebar, cut into 18" sections
A hair dryer from Goodwill
And then I picked up crucibles and stirring sticks from Amazon.

Crucible: https://www.amazon.com/gp/aw/d/B01N249H8C/ref=sxts_1?ie=UTF8&qid=1518276185&sr=1&pi=AC_SX160_SY231_QL65

Stir stick: https://www.amazon.com/gp/aw/d/B00C11IROW/ref=mp_s_a_1_3?ie=UTF8&qid=1518276272&sr=8-3&pi=AC_SX236_SY340_QL65&keywords=graphite+stir+rod&dpPl=1&dpID=21NmEPBFeXL&ref=plSrch

And then it's just tongs, gloves, etc. I spent about $300 total for all the parts, and had a blast putting it together. It's basically an inch and a half of mortar painted onto the inside of the bucket, 1/4" at a time. Set up the hole in the side for the pipe, and mix a little water with the extra mortar and pour it into another bucket to make the lid. Add the U-bolts for handles, and then set the rebar across the top to hold the lid.

It's fired by charcoal briquettes, and gets up to about 1900°F. It'll melt most of the precious metals, aluminum, copper, lead, whatever you need. Seriously, the crucible glows red when I do it.

I'm firing it up tomorrow to melt some pop cans and make ingots, I'll share the results tomorrow!