1. DO NOT DOWNLOAD OR TRY before you buy, some of these sofware applications integrate into all aspects of your computer! Some of these software can be Malware which may harm your computer or they may not even do as good a job of translation as you thought. Read independent reviews or watch videos first where available. Do read the comments of previous users first before making any drastic moves. These comments are usually available to view on You Tube or you can google the translation software that you saw being advertised. This is an example of the comments for one translation software, visit this You Tube page link: http://www.youtube.com/watch?v=B3LpmspD398. The comments were viewable as of 19/02/13. If it has been switched off since or if you would rather see those comments here then see below or this link http://www.complaintsboard.com/complaints/babylon-8-translation-c364620.html
"…its acting weird…the system task-bar agent is sending me warning violet messages in all languages, I'm just angry with that program interference… and the funny thing is that I'm the one trying to unistall it!!.I finally think is just one of those software jokes…"
2. Where the translation software is available free like, Google translate, try not to depend on the one translator as it has been known to give a slighty warped translaion. So what you could do is to use Bing Transalator with Google Translator for example.
3. Have someone check the machine translation if you need it for something important like an article or important document.
4. Some people are fortunate enough to have two or three computers. Maybe a laptop which they use for online internet searches and downloads and another computer for offline work which they use for personal pictures etc, so as not to fall into harms way from hackers or viruses. If you want to download and try before you buy any translation software, or any other software, use a laptop which has been around for a while, which you do not mind taking to the shop to erase or fix any issues which may arise.
To pay or not to pay that is the question…for you.
Good Luck with your Machine Translation