You all recommend the APIs, but as you already mentioned they have some limits, if we want to make unlimited requests we have to pay them. But I'm looking for a free way to do it. I main, bitcoin is open source, and paying for their services is kind of non-sense for me.
You pay someone who prepared API, who host server, pays electricity etc. It has nothing to do with fact if software they use is paid or not. Take an example:
https://nextcloud.com It is for free, you may use it to host your files, contacts, calendars etc. But if you want someone to host it for you, you must pay.
Maybe just find 500GB on disk and keep the full blockchain locally. Or import founded/historical addresses to the local database.
Could you tell us more what is you use case? Manual check or from application?