Spotify's API allows anybody to access information about various songs, albums, artists, etc. You can also create applications that manage playlists and can play any audio that is available. They have a free plan, but only allows 500 requests per month. Their premium plan is $10 per month that allows up to 10,000 requests per month, plus $.001 for each additional request.
This API returns quotes from popular movies and people. The first 50 requests per month are free, followed by different plans that range from $5 - $30 per month.
This API provides up-to-date odds for sporting events throughout the world. Data is collected from US, UK, EU and Aussie bookmakers, and is often used for betting purposes. The first 500 requests per month are free, with other plans that range from $25 - $99 per month. Their most expensive plan allows for 4.5 million requests per month.
Data is a valuable resource that people are willing to pay money for. APIs like these provide data for the public to use for their own purposes.