Best way to buy speaker cables and to evaluate them

I used TMR extensively because of the 30 day return. I buy mostly used. Their sales people know the products and can steer you in the direction your after. 
Check out Viablue they punch way above their price point and will provide everything your system is producing up stream. 

I would highly recommend World's Best Cable their Ultimate series comes in 12 all the way to 7 AWG.  They are on Amazon and they have a free 10 year replacement warranty.  They refund you the return shipping as well.  What have you got to lose?  Try em and if you don't like them absolutely risk free returns.  More cable companies should follow suit if they are confident about their claims.

Thanks for the recommendation. One of the other questions I wanted to ask when buying used cables is how do you tell if they are genuine or counterfeit?

I suppose that’s always a concern, but AZ is very liquid on the used market and I’ve never heard of anyone getting counterfeits for what that’s worth — my guess is they’re just not quite big enough for counterfeiters to be interested but who knows.  And if you buy from someone with a 100% positive track record that probability likely goes down to near zero.  Anyway, past these I’d also second the recommendation for the Silversmith Fidelium cables that get stellar reviews, aren’t horribly expensive, and you can return them less shipping so low risk.  Veritas cables are also worth a look for the same reasons.  Best of luck. 

Beg, borrow and steal Lol!!!  Happy listening.

@ghdprentice   while these words come from review, but they are similar to many ads.

Right from the start, what was most apparent was how fast the Fidelium cable sounded. There was so much more detail, openness, and musical information that it was almost an assault on the senses, but in a very audibly pleasing way. The Fidelium produced tonal colors that were vibrant and energetic. With the Fidelium, instrumentals and vocals were delivered with a considerable amount of presence, realism, and believability. Upper frequencies were provided with an increased amount of airiness and clarity. Percussion kits possessed newly discovered bits of information, and sounds, previously hard to identify, were now easier to follow. There are still items on percussion kits that I have no idea of what they are called, but with the Fidelium I can easily tell what they sound like. 

Well, I bought a pair of these cables, waiting for the magic, but once again I heard no improvement in my systems sound.  In correspondence with the owner of Silversmith, he asked what cables I was currently using.  When I told him I had a pair of XLO Signature 5.1 cables, his response was "yeah, I wouldn't expect to hear much difference between those cables"  so the Fidelium cables went back.