On the cheaper end of the spectrum, you can just make your own.
I bi-wire my speakers (not bi-amp), and had purchased a couple hundred feet of 14 gauge OFC cable from Crutchfield, and braided 4 strands of identical length for each terminal, and bought high quality banana plugs. Sounds great in my mid-tier, revealing, system
The quad braid with 14 gauge wire is the same as going with a single 7 gauge wire.
But, you only want to use that quad braided wire for your bass and midrange terminals...use a single 14 gauge wire, or smaller, for your treble terminals.
Good luck.

