An economic effect of the French and Indian War on American colonists was that

The major economic effect of the French and Indian War for American colonists was that they were taxed in the 1760s and 1770s to pay off the debt that the British took on to fight the war in North America.

An economic effect of the French and Indian War on American colonists was that as a result of it, new taxes were imposed on them.

Explanation:

Economically the war was disastrous for both parties. Public debts in the two countries threatened to bankrupt the Public Treasury. Both reacted by raising taxes enormously. The difference was that Britain applied them to American settlers and France, having lost their colonies had to tax the lives of their citizens. The taxes on the tea trade and the law of the Bell were notable.

Finally, and not so directly, this war could lead to the Revolution of the colonies against British domination. As mentioned earlier, Britain imposed exorbitant taxes on its colonies that drowned its economy, which led, among others, to the Boston Tea Party. Furthermore, as predicted by both British and French during and immediately after the French and Indian War, losing the settlers to the only neighboring power capable of defeating them no longer needed the British army to defend themselves. The only enemies they had to face were the natives, who had hitherto been able to bend. England had forced many settlers to actively participate in the war, so many veterans lived in the colonies who knew how to apply war tactics and, more importantly, had discovered that they were capable of defeating major armies.