Ebay won't allow ammo sales to my knowledge, but the empties are fine. You could sell the full ones locally or somewhere like this.
Couple of years back I came across a full case (20 boxes) of those blue/yellow Western Expert shells in 16 ga. 9 shot (or 8 shot). The idiot who had it had opened the shipping box to look at them
, but other than that they were intact aside from scuff from contacting each other in the box. I paid $200 for the whole case and thought I got a pretty good deal. I thought finding a full case was rather unusual.