There are usually a fully functional 15-30 days free-trials for Adobe Acrobat, Abbyy Finereader, PDFelement 6 Pro, Foxit Editor etc. usually just with an applied watermark which could be stripped off later on, or as is still the case with Abbyy enforcing 100 pages total restriction that could e.g. be circumvented by using several computers or OS, reinstalled OS, virtual machines etc.
There are also free OCR solutions like Topocr, Freeocr ...
https://www.makeuseof.com/tag/top-5-...-into-text-nb/
https://windowsreport.com/ocr-software-windows-10/
Some Pdf conversion tips on Willus' k2pdfopt pages.
http://www.willus.com/k2pdfopt/pdf_conversion.shtml