Why did colonist resist the tea act of 1773 even though it wasn't a tax?

The British were directly selling tea at a bargain price to the people, which you would think would be good, but that meant that they were undercutting the tea sellers in the colonies. Also, the people deduced that the British weren't taxing the tea to make the colonists feel better about the other taxes they were paying. And the colonists didn't like it.