The reason the cd would go for 50.00 is not the quality, but the rarity. Those who are Ozma collectors (and there really aren't many. The only people I know of with serious collections are Jason and DanielPhase2) specifically look for out of print material, and when there is a market for this rarity, it thus makes a damand. Ozma made limited home pressings of Inaudible, and an equally limited number were available through mp3.com as Audible. There are a few other fairly rare recordings (Ocho and Quatro, and a tape single [Just Tell Me When or Lorraine or something...I forget), the picture disc for RRP3, the radio release of domino effect, etc), but in general, since they only released a few albums and are now defunct, the demand has likely died down. Who knows?
Only time will tell.