Your best chance is in the LinkedIn and Facebook surveys. There are 4 licenses up for grabs online, one in each of the surveys outlined MindManager 9 License Competitions.
Is it worth 5 minutes of your time? Here is a Google search of MindManager 9 reviews. It will probably take you longer to read a few of these than enter one of the competitions. Your chances of winning the £244 inc VAT license are currently better than 1 in 100! That is the UK price but the license can be used in any country.
If you win the license you can give it away but I need to know the end user. Perhaps a student would find it useful for researching or your aunty for doing genealogy research or your business partner for working with you.
If you are a Mac guy you could run the license in Parallels or give it to one of your frustrated PC user friends.