The last cable I bought was a 10m length (0.75mm)—nicely transparent with a red marker on one side—for less than $2 a pack.
Otherwise, I have some old wire that came with a pair of used speakers; it’s very thin, and I strongly suspect it’s just standard electrical wire. It has a black marker on one side, so you have to be careful not to mix up the polarity; otherwise, the sound goes completely out of phase and the soundstage collapses.
The sound is, of course, extraordinary.
Otherwise, I have some old wire that came with a pair of used speakers; it’s very thin, and I strongly suspect it’s just standard electrical wire. It has a black marker on one side, so you have to be careful not to mix up the polarity; otherwise, the sound goes completely out of phase and the soundstage collapses.
The sound is, of course, extraordinary.