"FREE" is a very powerful word. Do not advertise "Free samples" if you expect the user to pay for postage or something else. If you abuse this word (or any others in the list) you've lost your credibility and your sales will plummet. Free means that the consumer will not have to pay for anything!
Use these words to express your product's benefits rather than it's features. For example, don't say "This software has x, y and z"... instead say "This completely-guaranteed software will save you time and money because it has proven x, y and z".
Words you should avoid like the plague!
In the same fashion, there are some words that scientists and psychology professionals suggest you avoid because they make your prospects want to stop reading. Here's the list of words that you should try not to use in your writing...
After you've written sales material... NEVER send it out immediately. Always put it aside for at least 24 hours and then come back and read it. You will almost always find mistakes or points that could use some improving to make your message more enticing to the reader. You should also show your writing to your friends and have them critique it.
