By the time you are reading this, last week's effort of subreddits (imagine shareable links that can be commented on by many within a Reddit community) going private where only the Mods can see content and its subscribers can neither see nor access the subreddit).
Reddit changed its API usage policy so that it now charges $0.24 per 1,000 API calls; whereas for the past x-number of years API usage was free to developers. Most for-profit companies will charge for API calls; sometimes this is baked into the service contract for enterprise platform licensing and sometimes API usage is charged at the per user per month/year/time period rate. It is not unusual to see online platforms doing this. Even Google charges for its Maps API.
Apollo is a freemium app; meaning that sure, there are features of the free version of it. But, to get access to other features, Apollo Pro costs a flat fee of $4.99 and Apollo Ultra has a subscription cost of $1.49/month or $12.99/year. The app's paid features allow users to manage multiple accounts (Reddit's app only allows one user account per current login session). Apollo has 1.3 million to 1.5 million monthly active users, and of that 900,000 daily active users. Each Apollo user consumes about 10,000 API calls per month to Reddit servers. The Apollo app makes about 50 million API calls per month.
App developers like to point out that Imgur's API pricing is much lower; but they fail to also disclose that Imgur is a free image hosting app. Imgur isn't charging customers to use their services for image sharing because the site is ad supported.
Here's a thought. Why should Reddit shoulder the maintenance and server costs for all the API calls made by 3rd party vendors?