And I Quote

"The people of the U.S. owe their Independence & their liberty, to the wisdom of descrying in the minute tax of 3 pence on tea, the magnitude of the evil comprised in the precedent. Let them exert the same wisdom, in watching against every evil lurking under plausible disguises, and growing up from small beginnings."
--James Madison

Three cents per pound of tea was the lowest tea tax in the British Empire at that time.  In the American Plantations as we were called in the Act, tea was sold at a lower price than in London.  This was by design.  The colonies had argued that we were not legally required to pay any taxes levied by the Parliament in London (this is historically correct, we had the same type of charter to form legislature, granted by the king that formed the Parliament in London). So the price of tea was cut below market rates and the tax was reduced to 3 pence per pound from 2 schillings 6 pence per pound for tea delivered to colonial ports.   The intent was to make tea so inexpensive and the tax so low that the colonists would just go along and pay it.

To put this into prespective I am brewing a cup of Lapsong Souchong. This is a fairly expensive tea at $35.65/lb.  I doubt that in modern terms the tax would amount to more than 25 cents American.  There was a principle at stake, and the colonists were not going to give into incremental taxes or incremental loss of their liberty.   One can only wonder what happened to their offspring.