With the show being run on TV, it's probably
being discovered by a new group, probably people who've
never collected before 
and have no idea that there are better prices
out there. They probably checked ebay and just overreacted
with what they found. 
With the TV series and the OAV, there should
be cels out there for more reasonable prices. 

I personally hate ebay. For the buyer it sucks
and for the sellers it's like Disneyland and
Fantasy Island wrapped together in one sweet 
package.