Yes, thank you!
Indeed you can buy bismuth crystals online, at one point I stumbled across some for sale. It's pretty stuff, very colorful.
Its sold on ebay, for example.
And, its not that expensive. Maybe $30 for a kilo if you're not looking for mineralogy specimens for display as art.
I don't know how toxic it might be in its pure state, it might be. That should be easy to find out, though.
Suppose one had some raw bismuth, and some lead and tin.. I suppose you could combine the three fairly easily in a pot. But then you would have a solid block, much less useful than solder wire.
How could you get wire?
It might be worth it to save money, if you saved a very lot. And used a lot of it.
But I guess we all likely would like to know if any of the better very low melting point solders (desoldering solders) are a particularly better deal than the others, if we buy slightly more?
I know that I just hate paying too much for anything.
I don't think your original question was actually answered (and my post also didn't help, sorry about that).
Low melting-point solders are principally composed of bismuth and/or indium. Bismuth is somewhat more expensive than tin, and indium is quite expensive, around half the cost of silver. But what we really want is a solder that can alloy with either Sn60Pb40, or lead-free, and form a combined alloy that is still low melting (and maybe has a wide plastic zone). I remember some user here from Eastern Europe said that he could buy some bismuth alloy very cheaply compared to what ChipQuik costs, but I don't remember the details.