Don’t let the 90% off fool you… this device isn’t even worth 20, let alone 200… get the Colgate branded one off amazon for $17.99.
$300? I’m thinking our friends at woot! added a digit or two?
You can make anything a deal if you just set the price to a stupid amount. Instead of $300 and a 93% price reduction… why not just say it MSRPs at $10,000 and sell it for nearly 100% off. 
Keep in mind the company also does not sell replacement heads.
You don’t have to worry about buying a replacement head (there aren’t any) because the novelty of this toy will wear out long before the toothbrush will.
ROFL. From the site you linked:
I was thinking it could be used for sonic cleaning, like jewelry or watch cases. Might work for that.
That’s what they mean by “augmented reality” 
I’ll wait for the “Augmented Reality” toilet paper to be invented…