dont spend allot of money, and dont worry much, start with something cheap. I had a wire running around 25 feet, into a cheap subwoofer, and I could hear the radio coming from them; however that was my only bad experiance with RCA wires.
My fear of RCA wires are based on the fact that any noise they pick up will be amplified. I dont buy into the speaker wire BS, but I would spend a little more money on some nice shielded cables. I spend around $20-$50 on a subwoofer cable, since its usually a long cable... The rest of my RCA's are the high quality RadioShack brand
However, if your subwoofer doesnt cost allot of money, then dont worry about it, buy a set of wires.
Also, your talking about under $10, and you just cost me about 15 minutes to respond... I will be sending you my normal consulting fee based on $150/hour.