You can get quite good speaker cables from Home Depot or Lowes.
Get two spools of SmithWire 12 gauge THHN stranded copper wire, one red, one black. Twist the wire 3 to 4 turns per foot between the amp and speakers. Use the bare copper if you want, or terminate with banana plugs.
It's an inexpensive and good preforming $25 alternative to $1,000+ cables.