True or False: Congress believed that the colonies could pay for war on their own.

I think it is mostly true that the Continental Congress thought that the colonies could pay for the Revolutionary War on their own. The reality ended up being that the colonies eventually paid all their war expenses, but those expenses included foreign loans from countries such as France and Spain. The economic war that Great Britain waged on its rebellious colonies had the Revolution on the brink of collapse before the victory at Yorktown, because the paper money that the Congress printed quickly became worthless due to its inability to collect taxes to back it, as well as rampant counterfeiting of the currency, and the states only contributed money and supplies when they could (and usually only to support their militia and not necessarily the army as a whole). However, the colonies paid for two-thirds of the war's expenses directly through printed and coined money, and only one-third of the war effort was paid for through the issuance of federal and state war bonds and foreign assistance. It took the enactment of the Constitution in 1787 to allow the now-United States the ability to raise the funds to pay back all its creditors, including the French.
https://allthingsliberty.com/2015/02/how-was-the-revolutionary-war-paid-for/

https://www.history.com/topics/american-revolution/the-continental-congress