First, you need to register and connect a Stripe account to use the Monetization features. Click on your username in the bottom left corner of the homepage and go to the Settings page.

Select the Monetization option and click the Connect button:

After clicking, the page will redirect to Stripe's registration or login page. Simply follow the on-screen instructions. Once the connection is complete, return to the Settings page, and you'll see a page like this, indicating a successful connection:

Click on Personal in the left navigation, then click on the App Tab at the top, and click the New App button to create an application:

On the application creation page, you'll see a Monetization Tab. Click on it to choose paid usage. Then you can set the price for single-use: