Bi-wiring is more marketing that reality and while there is proof that bi-wiring does affect things hitting the speaker, it has not once been shown that there is any audible difference by doing this.
Instead, as said above, simply pick up a couple pairs of standard 14... or even 12 gauge speaker wiring from almost any shop for a much more realistic price. Save your cash for something that actually will make a difference and take the sales pitches you have heard on audio quality due to cabling and throw them away. You have far better ways to spend your money.