The Anker TC930 isn't the only budget-priced iPad keyboard accessory out there: I found a TC950 on Amazon that's a full folio case with detachable keyboard for the same price. I prefer this all-in-one slim keyboard design, but you might feel differently.
The TC930 charges via Micro-USB and has a little on/off switch on the side. The keys are configured at around the same size and layout as other keyboards like Logitech's, too. Its number keys double as iOS-specific hotkeys if you simultaneously press Fn.
But, the drawback to the TC930 is -- no surprise -- keyboard quality. The keys feel clackier and cheaper than my favorite Belkin or Logitech cases. And I found that I got a lot of repeating characters when I typed quickly, which made me have to backtrack. It's a mediocre typing experience, and after all, aren't you buying one of these keyboards as a way to write more easily on an iPad?
In a pinch, for $30, this Anker Ultra-Thin is not bad as a basic travel keyboard, especially if you're using it to type emails vs. novels. But for serious typists, this isn't the keyboard you're looking for.