Yes, they really do cost that much. Well, I should say they did when they were available. About 10x the cost of a "PC" motherboard. By PC mobo manufacturers, I take it you mean people who make Intel boards? Well I doubt they would invest in PPC boards for Amiga unless they knew they would get a big return from it :roll:
Where have you seen one for $450? Are you sure it was an AmigaOne, not a PegasOS?
OS4 is available only to those who bought the AmigaOne board, and those who are beta testing the PowerUP version for "Classic" Amigas with PPC boards.
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moto