I think you are approaching the problem from the wrong angle.
A proper speaker cable is not defined by the amount of money spent on it. It's defined by the properties it exhibits.
A very competent speaker cable can be found for a reasonable price in most cases. Furthermore, a DIY solution, especially with speaker cables, is always an option.
Speaking very generally, as I don't endorse a product I haven't heard myself and come to a conclusion about. If you want a recommendation from me, I would suggest spending no more than about $100, and even at that price, you could spend less and get perfectly good results.
If you prefer to purchase brand name cable, one speaker cable I have heard and can honestly recommend is Morrow SP1 or SP2 (MSRP $150~190 2m pair, but Morrow runs essentially continuous sale prices and trade in discounts of 40% or more off; sign up for the newsletter and away you go).
One advantage of known brand cable is you can more easily resell it, although you will typically lose 50% from street price when you do. A DIY cable, regardless of how properly it's constructed, is difficult to resell. Even if you list it on forums that cater to DIY, the members there are perfectly capable of making their own versus buying yours.
Still, a competent speaker cable is not difficult to make yourself. Your choice of wire is vast, but Belden makes excellent speaker cable, choose the gauge you prefer. For connectors I like Vampire spades and Pin (like a banana) connectors. Pure Copper, gold plated, and for 10~12 AWG wire or smaller, about $12 for four. Hard to beat and you can do much worse for much more. May as well save the time searching and just go there. PartsConnexion, Douglas Connection, and others sell them.
Which brings up another option, and that is second hand brand name cable. As speaker cable is easily re-terminated, there is essentially no risk as long as the jacket hasn't been eaten by mice, or some similar damage. You can shop online (including here in the "for sale"; forums at Audioholics) or at resellers who accept trade-ins on cable.
Generally speaking, these are the things to look for (in my opinion ... I won't be arguing, if you disagree then make your own suggestions)
You want a good grade of copper wire ... at a minimum oxygen free, and if you want to improve on that, OHNO continuous cast ... and at an appropriate gauge for your amplifier power and the cable length. Then you want good connectors on each end.
CCA (copper clad aluminum) should simply be avoided, period. Arguments about conductivity miss the point. Aside from the low conductivity of aluminum (to be equivalent to copper, the rule of thumb is to add 3 to the wire gauge; ie 14 GA aluminum is equivalent to 17 GA copper, or 14GA copper is equivalent to 11 GA aluminum) it is brittle and stiff wire versus copper's outstanding malleability.
In practical terms that means you can lay copper cable where you want, and you can bend copper repeatedly without breaking while aluminum is likely to break at a bend and will almost certainly break if bent repeatedly in as little as two or three times.
Copper deforms in a desirable manner when crimped while aluminum resists ideal crimping behaviour, tending to break rather than deform uniformly, and any exposed aluminum (where the copper cladding has been removed or deformed at connectors) will corrode almost instantly with contact to air, and aluminum oxide is essentially a barrier to conductivity.
You cannot reliably solder aluminum wire, so crimping is your only option, or bare wire.
Finally, in general it's a good idea to avoid mating dis-similar metals whenever possible, for a number of reasons aside from electrical connectivity. As aluminum spades and bananas are essentially unheard of, it's difficult to maintain that ideal with CCA wire.
The connectors do not have to be pure copper, although that is what I prefer, and again you could decide to spend more for that feature, but brass is common and in my opinion OK (essentially copper plus tin and possibly other metals alloyed mostly because pure copper is difficult to machine while brass is almost ideal; brass as used in audio connectors is typically around 45% IACS* ),as the mass of any speaker connector is quite large, so you don't need the good grade of copper's 100%+ IACS conductivity in that application to be able to handle large currents. Remember that a larger gauge (or larger mass in this case) of connector with a lower conductivity is electrically equivalent to a smaller gauge with higher conductivity.
There are other issues with lower conductivity materials such as impurities and crystal structure that might impede transmission of audio signals, but it must be understood that these, if audible, will none the less impose subtle differences that might not be revealed in modest systems, or at least might not be cost-effective differences even if they are audible in modest systems.
Put another way, $300 in speaker cable (for example) might be better spent elsewhere in the system. If you've put together a system where you might need to spend $thousands to improve it's sound qualities ... maybe the next level preamp is double the cost of what you have now ... then maybe that $300, if you can hear a difference and that difference is an improvement (which is not always the case) then maybe it's worth going there. So these choices are very system-dependent. That must never be forgotten.
Finally, you don't mention how long your speaker cables need to be. There has been tremendous pressure, fueled in part by audio cable manufacturers, to utilize a large gauge conductor for speaker connections in particular.
Even if high current demands are present (high power in watts from the amplifier to the loudspeaker) the current carrying capacity of any wire is dependent not only on the gauge of that wire but also it's length.
When a sound system requires long length of speaker cable, you will often get advice suggesting a large gauge of speaker wire. Not so much when the length is relatively short, such as 10 feet or less. But it must be kept in mind that 14 or even 18 or smaller gauge wire will carry huge currents if the wire is relatively short in length.
That is not to say you can't use 12 GA wire for your 4 foot speaker cable run, but it is worth mentioning that many audio engineers design based on the theory that the best sound quality is achieved when using the smallest gauge wire that can adequately handle the required current and/or voltage.
Current carrying capacity is reduced when a cable is not in free air (has a jacket of PVC, foamed PE, PTFE, etc),and when more than one cable is in a bundle or in close proximity. Obviously speaker cables will be at least a bundle of 2, often 4 (bi-wire). The calculation will be the total length, so in the case of a 5 foot speaker cable the total length (+ and - runs) will be 10 feet.
There are many calculators online for resistance, heat losses, and power drop for wire and cable. Most are not useful to us as they are oriented towards AC power, electrical code, and so on, and assume things like jacket material and thickness that is common in electrical wire but not in speaker cables.
The best general resource for speaker wire that I've found has been around forever, is oriented towards car stereo, but none the less is better than the vast majority of charts and calculators you will find online. Others may have different favorites, but this is mine. Check it out here:
http://www.bcae1.com/images/swfs/speakerwireselectorassistant.swf
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* IACS refers to the International Annealed Copper Standard (IACS),which defines a conductivity of pure copper at 100%. Some coppers can have a conductivity higher than the IACS standard, thus 101% up to 104% copper is possible.
