How many denarii did the Good Samaritan give the innkeeper?

Answer: Two

He gave the innkeeper two denarii (KJV: two pence) and promised to repay any additional expense.

“The next day he took out two denarii and gave them to the innkeeper. ‘Take care of him,’ he said, ‘and on my return I will repay you for any additional expense.’”— Luke 10:35 (BSB)