To find the total cost of the app for \( m \) months, you start with the joining fee and then add the monthly subscription costs for each of the \( m \) months.
- The joining fee is $2.
- The monthly subscription cost is $5 per month, so for \( m \) months, the total subscription cost will be \( 5m \).
The expression representing the total cost of the app for \( m \) months is:
\[ 2 + 5m \]