Known quality, or at least the better, less expensive "branded" cables.
Monoprice and Cables 2 Go are my two "old reliables". Good price and they both make excellent cables. There are other brands that are more expensive, but they are in no way better cables. I've also seen cheaper cable makers, and its hit or miss. Sometimes its crap cabling (like copper clad aluminum) and other times the quality is just fine.
You can have various short cuts taken in cabling. Copper clad aluminum is the big one and a big no-no. It saves money, but the cabling is much more fragile and it does not meet specification (must be all copper conductor to meet Cat cabling specs).
Other times you'll find thinner PVC jacketing, not enough twists per inch, missing pair seperator (cat6 and higher) and so on.