Is there a way to practice with AIX if you no longer work for a company that has AIX? With RHEL you can use Centos, with Debian you can use Ubuntu. Is there something similar with AIX?
Maybe with QEMU ?
Buying a second hand small aix box... I heard long ago of a possibility of trying to install aix on a powerPC Mac, but when I got interested I could not find the resource anymore, I even wonder if it existed one day...
There is not a community version of AIX - such as RHEL and Centos/Fedora, and iirc, rather than Ubuntu you can use Debian (i.e., I thought Debian is always community while Ubuntu also has a supported version (Canonical).
Back to AIX and working on it - there have been initiatives from IBM to have "free" access to an AIX cloud image. I have never used one, and do not know how long you can use the image.
The most common path WAS to buy a POWER box (e.g., a POWER7 box should come 'affordable' for a professional wanting to keep in touch, OR - where I have been fortunate - once - a (previous) employer may donate (rather than trash) a POWER system they no longer use. Maybe they will leave AIX on it for you, maybe not.
For others - best to get something setup before you leave an employer who uses AIX.