The $1 iphone charger I took apart was such a poor design and construction. Very little isolation, so unsafe. two transistor resonant style switching setup, cheapest there is. Too small output capacitors making the output very noisy. Though it claimed 1A, it was dropping out by 300mA. Not even close. No input filtering at all. no fuse. I'm surprised the things work at all, really.
That's not to say that it isn't possible to make a good charger for less than a .. whatever ripoff pricing apple charges, $30? There should be room to profit on a $5-10 charger, and meet all standards... But the $1 ones are absolute garbage, and no one should use them, ever.