I get this question all the time, "Do I need to spend a lot of money on wire?" The short answer is no. It's like asking if you need to drop $50 or $100 to buy a good bottle of wine. No, unless you're a wine connoisseur; most folks are perfectly happy with a nice $10 variety. True, you'll use a cable a lot longer than it takes to drink a bottle, but I wouldn't recommend spending more on a single set of wires than you'd spend on wine--unless you're an audiophile.
Audiophiles obsess about the tiniest details of sound quality. That, and we frequently listen attentively, an activity few non-audiophiles ever do. Everybody else puts music on and then reads, talks, works, exercises, or cooks. So if you're not really listening, I wholeheartedly agree, spending money on expensive cables isn't a smart move. Another thing, you'd have to own a pretty decent set of speakers to hear the benefit of better cables, and if you already have a set of great speakers you're probably an audiophile.
So all of you non-audiophiles can rejoice. Don't let anyone talk you into spending a lot of money on a speaker or interconnect cable! Head on over to your local hardware store, Blue Jean Cable, or MonoPrice and buy dirt-cheap, decent quality cables.
But before you buy a speaker cable from anybody, first grab a tape measure and determine the lengths of each cable; accurately measure the distances, including running the wires over furniture or doorways for each speaker. And measure the distance to the subwoofer from the receiver, which probably needs an interconnect cable. If the speaker wire packaging lists a "gauge," 12 to 20 gauge would be fine; the higher the number, the skinnier the cable's metal conductors will be. So 12 or 14 gauge might be too thick to squeeze into the speaker and receiver's connecting holes, but if you need to run long lengths, more than 25 feet, go for the thicker stuff. Trim away enough strands at each end to squeeze the remaining strands into the connectors' holes.
"Unterminated" bulk wire is the cheapest way to go: MonoPrice sells 100 foot rolls of 14 gauge wire for about $17.34. For comparison's sake, 100 feet of MonoPrice's thinner 18 gauge wire goes for $9.21! In either case, it's good, "oxygen free" copper wire. MonoPrice rules!
Once you have the wire at home, cut it to the lengths you need, and strip away a half-inch of insulation at each end to expose the bare metal strands. Twist the strands into a bundle to eliminate any loose strands. It's extremely important to closely inspect each connection, at the speaker and receiver ends to confirm that no stray "+" wire strands are touching "-" strands. If they touch they will "short" and trip your receiver's protection circuitry, or blow a fuse, or in the worst case scenario, damage your receiver. Check the connections, and check them again before you turn you the amp on.
While you're checking for loose strands also confirm you didn't accidentally reverse any of the "+" and "-" wire connections, at the speaker or receiver ends. Speaker wire or zip cord will either have a raised ridge or stripe on one side of the cable; make sure you consistently attach the raised side or stripe to the "+" connections. Failure to do so won't harm the receiver or speakers, but the sound of the reversed connections will be "out of phase." Translation: the sound quality will be off.
If you think you'll need to disconnect the wires from time to time, splurge and buy MonoPrice's nice, all-metal banana plugs that run $2.28 per pair. With the banana plugs it's easy to plug and unplug the wire connections. Before you order the bananas, look at the speaker's and receiver's connectors to determine if they will accept banana plugs (if you're not sure what you're looking for consult the owner's manual). With the MonoPrice wires I just described, you will have to attach the bananas yourself. No big deal, it should take just a minute per banana.
Or buy "preterminated" speaker wires with banana plugs already attached, from Blue Jean Cable. There you can order custom cut lengths of pairs of speaker cables, for example, Blue Jean Cable sells pairs of 10 foot "Belden 5000UE 12 AWG Speaker Cable" with banana plugs for $32.25. Of course, Blue Jean also sells unterminated cable, for a lot less--$10.40 for that same pair of cables, with no connectors.
If your powered subwoofer didn't come with an interconnect cable (most do not), check out Blue Jean's offerings. For example, a 10 foot BJC LC-1 Subwoofer Cable runs $24.25; a 20 footer goes for $36.50. The cables are terminated with RCA plugs.
MonoPrice and Blue Jean Cables also sell video cables and a vast variety of adapters for great prices.
There's no reason why bona fide audiophiles should automatically turn up their noses at MonoPrice and Blue Jean's wires. They are perfectly good wires; however, I use XLO Signature Cables and Zu Audio cables in my system. And yes, I hear worthwhile differences in the sound of better cables. If you don't that's fine with me; invest the wire budget money in better speakers, amps, and so on.