I hate to see cels bought and then sold a week 
later on ebay.  But I had to do the same thing, 
and so I can't be as harsh about it as I used to 
be- sometimes a person needs a wad of cash fast, 
and ebay is usually the best way to do it.
It really bothers me to see dealers put brand new 
cels up on ebay instead of their own sale sites 
first, but the reasoning I have come up with is 
that they need the extra revenue to stock more 
cels on their regular sites.  
My thought on it is to try and sell things 
outright before posting them on ebay- it seems to 
give the less wealthy a chance.