Where can I buy lead ingots?

I'm posting this in the teaching forum in the hopes that some science teachers here have a "go to" shop for sciency-type stuff. If I remember from days gone by, lead is commonly available in 5Kg bars or ingots. Does anybody know where I can get one?

One possible extreme solution would be to buy a bunch of fishing sinkers and melt them down into a bar shape, but I'm hoping to avoid that much work if possible.

Thanks.