the search for lead goes on.

55 Cents a lb is about what I pay in South Africa.   The 15 cents you actually paid is so cheap its a joke.   But you are on the right track buying scrap in substantial quantities.   Which brings me to something that has always puzzled me.   All American sources ( books, magazines, forums ) focus almost entirely on wheelweights as if there is no other usable scrap.   There's nothing special about wheelweights except that they are in small pieces and thus easy to handle, and they contain some antimony.   But don't forget that you get 75lb of alloy from 100lb of wheelweights after the clips are skimmed off, so you are paying 33% more than the dollar cost.

Take all the sheet lead, pipe, or whatever other form it comes in, and set yourself up to melt it in big lots.   Dale53's set up is about the nicest I've seen.  We don't have those big fish/turkey cookers in South Africa.   I made up a pot from steel pipe, with a stand from angle iron, and I fire it with bottled gas like Dale53.   I also made my own ingot moulds from angle like those in his photo, but mine cast one pound ingots for continuous feeding of my casting pot.

The bigger the lots you can melt the more uniform alloy you get.   That's the time to blend in the antimony.   Its the only practical way to handle scrap.