Orb, best best I say, is to check any local sales, resale shops, etc. Years ago, I got 2 miggy MIDI interfaces in a box of computer 'junk', sold one, and sorry, I am keeping the one with 2 OUTs. it IS aggravating tho, I have the MIDI interface, OctaMed SoundStudio + like 3 other MIDI programs... but I can't afford a real synth... 
Midi Out from the Amiga to Midi In on your PC and feed it to as many VST's as you like.
No need for hardware synths.
