It provide wide variety of data objects, and also provide map view where possible to showcase the active region of operation ( its a unique feature of the API), plus heaps of data. You can test the API for free and access all the data objects.
All the comments above have made valid points related to IP geolocation APIs. There are already various free and paid IP-to-address APIs available in the market.
Some are expensive because of the effort their team has put into continuously monitoring the accuracy of their service and keeping the data up-to-date. It is one thing to build an API layer on top of the free data sources and provide for low cost, but keeping the operation running with high up-time, improving data accuracy daily, adding new data sources and handling ambiguity with location data is quite challenging and requires a proper dedicated team.
If you are a single person building this service, it can certainly take a toll on you. Nevertheless, there are many free APIs available which is just a wrapper on top of Maxmind's free data source.
But if you can build a niche group of people who willingly pay to use your service, it is possible and as you mentioned be able to offset the running cost.
You can try our ASN lookup tool: https://www.bigdatacloud.com/asn-lookup/
It provide wide variety of data objects, and also provide map view where possible to showcase the active region of operation ( its a unique feature of the API), plus heaps of data. You can test the API for free and access all the data objects.
Any doubts or queries, please let me know.