Amazon offers Prime members the Pyramid 12 AWG Speaker Wire 50-foot Spool, model no. RSW1250, for $6.50 with free shipping. (Non-members can spend $35 to qualify for free shipping; otherwise, it adds $5.70.) That's the lowest total price we could find by $9. Please note that colors may vary.

Update: Note that this item is temporarily out of stock, but can still be ordered at this price for delivery when available.