Which is better? Four dollars WAS enough to buy the new book? Four dollars WERE enough to buy the new book?

“the first decision that led to brutus’ downfall is when he decided that he would join the conspirators in their plot to kill caesar. the plot did not work. the conspirators had to flee for their very lives. the second decision that led to brutus’ downfall is when he refused to listen to cassius. “ i hope this information you.