To represent the amount of text messages \( m \) you can send given that each text message costs $0.15 and you can spend no more than $10, the correct inequality is:
\[ 0.15m \leq 10 \]
This means that the total cost of the messages (0.15 times the number of messages) should not exceed $10.
So, the answer is:
0.15m ≤ 10.