An obi is the little slip of plastic on the
outside of the item that says the name, price, and
maybe someother advertising stuff.  And yeah, that
is a little low, but LD really isn't chic anymore.
 It'll depend on the seller's attachment to it,
and the rareity of the item.  I have 6 or 7 LD's
(Utena vol2, Mononoke, On Your Mark (THIS NEEDS A
DVD RELEASE)), but no LD player, so if I was
forced to sell them I wouldn't be as attached. 
Just my opinion.