Someone has information about what can and can not be done with a trial version of mach3 for lathe, please if someone has a mach3 turn license for students that can provide me, it would help me a lot, or information about how this and where can I buy it?

Threading dose not work in Mach3 demo. You are also limited in the number of lines that it will run. Note that it is not 500 lines depending what is commanded. There is no student license available to my knowledge.

Here is link to where you can purchase a license:
http://www.machsupport.com/shop/mach3/

RICH