Amazon offers the RCA 16-Gauge Speaker Wire 100-Foot Spool
, model no. AH16100SR, for $10.99. Clip the 15% off
coupon on the product page to cut it to $9.34
. Plus, Amazon Prime members bag free shipping
. (Non-members can spend $35 to qualify for free shipping; otherwise, it adds $7.31.) That's the lowest price we could find by $2, although most stores charge at least $15. It features an insulated jacket with polarity markings.