Beware of cheap bikes...

...and be aware of who is assembling them if it's not you. This link details a recall of Huffy bikes from Kmart, but it sounds to me like part of the problem may have been poor assembly as well as cheap parts.

Bikes are wonderfully simple machines, but current manufacturing methods mean that in most cases you get what you pay for (e.g., poorly made parts, iffy welds). Note that the article does not say the cranks break, and that you can call Huffy for instructions on tightening the cranks that will presumably make the bike serviceable. But I imagine that's cold comfort if you discovered the defect in your bike in the middle of a long descent!

Please patronize your local bike shops! You won't pay that much more for a quality ride, and you get people who will not only make sure your bike is assembled right but that it fits properly. Both are important for a safe cycling experience.