I have a bottle of Optrix CD spray that's more than 50% full... I'm just not using it, so off it goes.  Sells for $16.99 plus shipping from Music Direct and others.
Asking $7 shipping included, which, again, is for a bottle that's over half full--enough to treat a good many discs.  Includes the box, too.  Only thing missing is the clear cap that goes over the top of the nozzle.  (It's probably around someplace around here--I'll include it if I find it.)
So if you want to try Optrix and not pay full price, this may be the way to go.