Cornbush is a plumber, and has gotten some for me in the past.
It's good stuff.
For a while, the local supply house was selling the 25 lb "chains" of 5 lb ingots at $0.60 / lb, certified. Like a bunch of idiots, we procrastinated and missed our chance. Now, the lowest price within 60 miles is $2.50 / lb for the same ingots/chains!