They're what is known as China Clay. They're a step or three above Dice chips, but not really Clay, and many would say that they aren't "quality". But they do target the budget market, much the same as the Royal Card Room China Clays and the Tina ceramics, and as such are a valid option.
You might consider that many members here spend $6-10 per chip (or more), so their perspective of quality and value is probably different than yours. As to whether they are worth $0.55 per chip, that's really a decision that only you can make. I will say that they are comparably priced with other China Clay chips. If they fit your budget, and you like the look and feel of them, then they will probably be just fine. And Apache is a reputable vendor with good customer service (in my experience).
But the standard recommendation is to get samples of different options before you decide.