There are so many software tools around - most of them are shareware - meaning that they creators are only giving you a trial version for a limited time say thirty days and after that period lapses, you would need to buy the license for the programme to continue using it. It is a good concept - if you like their work, and want to continue to use theis software, they should be compensated by way of a small fee/donation. This would serve as incentives to provide users with an updated software. If the time for the trial use had lapsed, the software may display intermitten reminder... or appear in your printed documents (to your dismay) or even refuse to work.
I personally love freebies. There are so many around. If you are into the Open Source Movement, you may had came across or even used Open Office as your productivity software. For Open Office, there is an inbuilt tool that could convert whatever document that you are working on to PDF format. End of story.
For microsloth lovers, look out for PrimoPDF - it is a small software (really tiny) that acts as a software printer. Just open your document (any document) and click on the print button within your software - remember to select PromoPDF as your printer. The output is your document is pfd format.
More information : http://en.wikipedia.org/wiki/PrimoPDF