Actually, a Japanese cel collector told me he got
several nice Lodoss OVA cels with backgrounds for
around 2000 yen ($19) each.  Of course, that was
many years ago when they first released.  At that
time, he thought they were expensive.  Now they
worth 50 to 100 times higher.  However, he said
he already sold them a few years ago at around
10 times higher than what he paid for.  Still
pretty good profits, but if he kept them for
a few more years till now, he would make a lot
more.  

Fortunately, I'm not interested in Lodoss.