Using inexpensive CAT6 plenum cable - solid copper, not aluminum, you can make an exceptionally good speaker cable:
(from the silversolids.com Blog)
Jung and Marsh stated that their tests showed that the use of multiple thin gauge solid core wires in parallel was the best way to go. This gives you low capacitance with no phase or skin effect problems in or directly above the audible range.
When asked, "What is the real thing about using silver in audio chain?" Mark Levinson replied: "Silver is the best conductor of electricity. Laws of physics. But copper is more practical for speaker cables.".
For a speaker cable, using just one pair of 23 ga. conductors results in a noticeably lean tonal balance but grouping multiple light-gauge wire gives you an even tonal balance without diminishing the desirable high-frequency performance advantages of thin gauge wires. The most cost effective way of achieving this is using plenum type CAT6 Ethernet cable with eight pure copper 23 gauge solid wires and Teflon dielectric in multiple pairs. Uncompromising high-end caliber performance at a bargain price.
The illustration below shows one side: 