Iria cels have been sold for $10 - $300 that 
I've seen, depending on who was selling and how 
nice the shot was. Lately I haven't spotted any 
for sale either, other than one on Yahoo Japan 
this morning and this cel on a gallery For Sale 
page:
http://zelgoddess.artchicks.org/celpage/salecels.
html#

I'd suggest looking over personal gallery sale 
pages and checking out Ebay and Yahoo every now 
and then, or just asking if anyone on this forum 
wants to sell one of theirs ^^