www.cutepdf.com is a site that the writer lets you turn your usual documents into more secure and reliable PDF documents really easily.
Once you have installed the programme, the option to save or print any web page or document as a PDF just appears in your printer list.
That is it really. There are no adverts foisted on you, no weird watermarks splurged across the pages.
And it is free because they hope that you like it so much you will eventually pay for their advanced version. But - of course - you do not have to