Well... If you really, really want OS4, you have three choices, wait until someone who has the hardware and OS4 on it sells it. Or, find someone who has it, and bug the hell out of them until they sell it to you, and last, find someone who has it, and make them an offer they can't refuse. :rtfm:
Otherwise, just put an emulator on your PC and enjoy what is already available, if you don't want to clutter up your desk with physical hardware.
Welcome to Amiga dot org. Enjoy your stay. :-D
