One problem with a $2.99 cable isn't that it "might break," it's that it might zap you with a "potentially-lethal 340 volts" among other less severe but still significant drawbacks (which most people wouldn't ever consider).
It's one thing with chargers, and another with cables. Apple's cables are actually worse quality than the cheap ones IMHO, since putting a proper strain relief on the cable violates Apple's design sensibilities.
I almost gottend zapped by one magsafe connector, and almost had another one cause a fire due to this. Apple of course insisted this was not their fault, until the next replacement charger "magically" had a 2-3 times as long strain relief.
You could just as easily get zapped with a "potentially-lethal 340 volts" with Apple's cables. Notice how that fake charger has a USB port to allow you to connect your existing iPod or iPhone charger cable to it, including a genuine Apple cable.
(I suspect that the chargers with integrated micro-USB cable are, for the most part, quite a bit safer due to not imitating Apple and having plenty of space. I actually took a dirt-cheap Chinese 5V supply apart a while ago because it had died - proper controller chip and all the works, good half-centimeter of isolation between high and low voltage, slot in the PCB along the part of the isolation boundary where they're closest, etc.)
http://www.arcfn.com/2012/03/inside-cheap-phone-charger-and-...