You'd ONLY gain a profit if a)you sold them and
b)someone actually BOUGHT THEM. As I stated before
LDs are essentially dead, almost NO ONE wants them. 

You can list them at 10 to 90, it does not matter.
At most cons I go to, they do not sell. Very few
dealers want to carry them and if they do, it is
only in the hopes to dump them and get rid of them
once and fo all. Only people who are avoiding
making the switch over the dvds are still wasting
their time buying/collecting them. 

The quality if usually worse and in terms of size,
they are horrible to store. I use to have a huge
LD collection; I sold the entire thing when I
learned about dvds. Does this mean I'll do this
everytime they have a new format? Hell no! 

IMO however, lds have too many technical problems
with laser rot. Dvds are smaller, possess greater
data and most importantly are cheaper and readily
available internationally. LDs aren't cels, so for
myself there was and still is NO way to justify
buying something that is a)not rare, b)something I
can get in a better format, and is c)cheaper.