Budget-conscious musicians. MuseScore is a free notation software that has a built-in PDF converter (powered by Audiverus OMR). You can open a PDF directly in MuseScore, edit the messy result, then export as MusicXML (File -> Export -> MusicXML). Afterwards, open that XML file in Guitar Pro.
: Offers an online PDF-to-MusicXML converter that is free for the first 10 uses. Important Tips for Success Can Guitar Pro Import PDF Files? [ANSWERED] pdf to guitar pro converter