Check with a tire store and see if they will give you some old wheel weights.
When I cleaned out my Dad’s shed, I found several old rusty coffee cans of wheel weights.
I went to Goodwill and bought a small cast iron frying pan and a muffin tin.
I put the pan on my fish cooker and melted all the weights down, skimmed off the impurities and poured them into the muffin tin, making a handy, easily-stored size for future use.
from what i've read, you don't want to use wheel weights to use in lures.
there are too many impurities that make them brittle and don't pour full form.
i use wheel weights to pour egg sinkers, 2-12oz and solid 1-7lb. for deep dropping. haven't tried any lures with this lead, it may work for you.
The bullet casting forums will often have folks selling ingots.
Alloys will vary from pure lead to lead/tin/antimony in different ratios for different bullet/ammo applications.
The ingots are not too costly and are generally good, clean alloys that save you some of the fluxing, skimming, etc. Wheel weights will require a good deal of fluxing, etc. to arrive at clean material. A lot of wheel weights can be zinc as well; you probably don't want zinc in your alloy.
Tire weights are not lead anymore, it's some other composite type stuff. You still may get some real lead tire weights from a tire store, but not much as the tire stores do not use lead anymore either. And if you do melt your own lead, such as tire weights, when melting it, put some sawdust in it and mix it in. It'll burn up, but the ashes (now carbon) will help remove impurities and add antimony back into the lead.
I don’t know how old the tire weights were that I got from Dad’s shed but they were lead.
They could have easily been 30 or 40 years old.
When I melted them down, the impurities rose to the top and I skimmed it off. I don’t know how pure the lead is but it’s good enough for anything I need.