One of the economic effect of the French and Indian War on the American colonists was the start of "mistreatment from the British government".
This includes:
Increasing taxes: Because the war with France drained most of Britians coffers, the British government decided to tax the colonists, since they weren't paying as much tax as the people living in England. This led to a rise of hatred towards Britain, because the American people didn't think it was fair.
Increase number of British troops: Sure, you can argue that the British sent troops later on to "protect the colonists" (before revolutionary war), but most of them were there already due to the French and Indian War (they had to fight the French). This meant that the British troops already there had to be taken cared of, and usually they were housed in colonist's homes. This put a strain to the Colonists, because they had to pay for taking care of unneeded troops.
These are just a few. Hope this helps