Welcome! It's always nice to see someone new getting involved. The Amiga can be a strange beast, but I hope you're having fun with it so far.
1. Unfortunately it's very expensive to get OS4 going on real hardware. The cheapest option available now is probably one of the boards from ACube. Odds are that you'll need to order it from abroad, if anyone has them in stock. Have a look at dealers like Vesalia, Relec, Alinea, and Amigastore (in Spain). There are others dealers out there but I can't recall them off the top of my head.
There is a new board in development called the A1222, aka Tabor, that should be in the mid-hundreds range when it comes out. Not sure when that will be, though.
High costs are due to the low production volumes for the small market.
2. MorphOS is Amiga in everything but name. A short history: in the mid 90s official Amiga OS development was stagnant. Various developers came up with new standards to extend the existing operating system. In most cases, there ended up being two different standards for similar functions (GUI tool kits, graphics APIs, file systems) When PPC accelerators for the old Amigas appeared, some developers started a full reimplementation of the OS to run natively on the PPC (as opposed to the PPC being used as a coprocessor under the old OS). This reimplementation became MorphOS. Later, formal AmigaOS development started up again and the result was two Amiga-like operating systems descended from the original OS. Generally speaking, MorphOS ended up with one set of the late-90s APIs and AmigaOS4 ended up with the other. Point being, both can trace their roots to widely accepted - but different - Amiga standards.
MorphOS has a higher software cost than AmigaOS, but given that the hardware is cheap and easy to find your whole investment outlay will probably be a lot less. MorphOS has a very generous demo mode. You can install and run the OS as much as you like, but the system will slow down to be effectively unusable after 30 minutes of uptime. With a quick reboot (~5 seconds) you can continue working. Registering removes the time limit.
2.1. Politics. We don't know why AmigaOS was never ported to Macs. It would have made a lot of sense, although a few of the more... eccentric members of the Amiga community railed against it as corrupting the platform or some nonsense like that. Thankfully the MorphOS guys did it, though, which has made it far more accessible than OS4 (although that has finally started to change now that OS4 can be run under WinUAE). There was an AmigaOS port to the Mac Mini in development, but an alpha got leaked/stolen, a bunch of people got mad and that was the end of it
3. WinUAE would be your cheapest and most space-saving option
. But only you can decide whether you want to play with real hardware. My recommendation would be to continue with WinUAE for AmigaOS and get a little Mac Mini for MorphOS. There's also AROS, an OS reimplementation for x86, but I know almost nothing about it, especially recent developments.
Hope this helps! Keep asking questions!
