Monetizing your bot
Monetizing your bot, of course, is entirely optional and how you monetize it is dependent on the function of your bot and whether there is a market. Bear in mind that if your goal is to sell your bots for a one-off price, the Slack app directory does not support monetary transfers.
All apps in the app directive are free to install, but how you convert your user base to paying customers is left up to you.
There are a variety of methods to do this and there is no single correct way or Slack-sanctioned method. A popular method employed by companies such as Zoho Expense (https://www.zoho.com/us/expense/slack-integration/) is a payment plan based on users. The service is free for small teams, but once you require more than three users to have access, you have to migrate to a paid tier.
The idea here is similar to APIs we have encountered, such as Wolfram Alpha. This means using a tiered approach where a free tier exists (tied either to amount of calls made or an expiration date...