Some people manage to get copper wire from compagnies doing electric work. They strip this from the plastic, and then anneal it.
For me personally, I buy it when I see a good deal somewhere.
Price per kg is maybe twice that of aluminium. But as you need less thick wire than with aluminium, you save on the amount you use.I find it has A LOT more holding power than aluminium. And is less visible, which I find important too. And of course.. 1mm think wire on a 1mm thick branchlet looks silly. So better to use copper for fine wiring, in my view.
