Kiersten runs a website that helps people learn programming. Every month, Kiersten receives a subscription fee of $\$10$ from each of the subscribers to her website. Last month, the website had $100$ subscribers. This month, $30$ new members joined the website, and $10$ members cancelled their subscription. **How much money will Kiersten’s online business earn this month?** $\$$ [[☃ input-number 1]]