To find out how much money Garrett has left after buying the pencils, we first need to calculate the total cost of the 10 pencils.
The cost of one pencil is $0.15, so for 10 pencils, the total cost is:
\[ 10 \times 0.15 = 1.50 \]
Now, we subtract the total cost of the pencils from the amount of money Garrett initially had:
\[ 1.74 - 1.50 = 0.24 \]
Therefore, the amount of money Garrett has left is $0.24.