Do you realize that most Amiga software is PAL specific and will work on a 60 Hz 1084 series monitor? It's switchable! The only thing you'd need is a 60 Hz power supply for a PAL A500 in the U.S.
The only real use for an NTSC Amiga is to hook to an old television.
Also, the A500 has the Kickstart in ROM. Only an A1000 or early A3000 needs a Kickstart floppy disk.