Well, OBi prices are as fluid as the "market price" of a lobster on the menu at a restaurant.
Today's price shown here on the left side of the forum page is $59.99, and the price on Amazon and Newegg is 57 cents higher. The $49.95 price is only shown on the GIF on that page, and it's likely just an expired price from the last time the device was on sale. Promos come and go all the time. I suppose, if you want to get a lawyer involved, you could force them to give you another 10 bucks...