There are several free and good-performing PDF editors for your choose:
PDFBuddy:online site that allows users to edit and manipulate PDF files
PDFescape:online PDF reader and editor
Skim: PDF reader and note-taker for OS X
Preview: zoom, split, merge PDFs, add highlights and notes, rotate, add bookmark, protect PDF, and export to other editable formats.
Readdle PDF Expert: Mac PDF editor to edit text, annotate, fill out and sign your documents
Cisdem PDFManagerUltimate: read,sign, merge, split, compress, encrypt, and convert scanned PDF files with advanced OCR technology.