When i went to go and see avatar a few weeks back they asked if i wanted 3D glasses-which i said yes too. But they also said did i have any already, so i'm guessing the reason why the ticket was
depenRAB, there are several 3d tech. 3d imax, dolby 3d, real d 3d etc. real d is disposable, so that might be the one you can bring back. dolby uses more expensive ones and they wash/sterilize between showings so i doubt you can easily buy your own.