AIX Trial Version

Hello,
I'm now trying to learn AIX and I found lot of used AIX machines in ebay. I want to clear some doubts before I go for one.
1)Do I need a license to run an AIX machine?
2)Is there any Trial versions available?
3)Some Old Models of AS400 machines( model 150) don't need a license upto certain vertion of operating system. Is there such a facility in AIX?

Thanks in advance.

There is no such thing as a trial version, but AIX machines are usually sold with an OS license. Make sure you get this license when you get the hardware. Most of the times it is included anyways, because the new license is most of the times included free of charge in the purchase of the new hardware.

I hope this helps.

bakunin