There are almost no programs, Shareware or otherwise, that are much use for editing PDF files. Foxit Editor is Shareware. OpenOffice 3.0 Draw can open PDF files but each line of text is a separate object.
The best at a reasonable price is PagePlus 11, but you have to understand that you cannot edit a PDF file like you can an imported word-processing document.
Each page will be at least one separate text frame — maybe dozens of text frames.
Why do you need to edit PDF files?