Smile has announced a special Back-To-School discount of 50% on all four versions of PDFpen. PDFpen is a PDF editing tool for adding text, images, and signatures; making corrections to PDF documents; filling out PDF forms; converting PDFs to Microsoft Word; and optical character recognition (OCR) of PDFs for easy search. ($29.99 with the discount) PDFpenPro has all of PDFpen's features, plus the ability to create fillable forms and edit a PDF's table of contents. ($49.99 with the discount).
If it were me, the discount makes PDFpenPro and the iOS Apps a no-brainer. I recommend buying the Mac App Store version as it's required for iCloud compatibility. The discount expires at midnight Pacific time, Monday, September 2, 2013.
Disclosure: Smile is a sponsor of Mac Power Users