From glossa and the base of kosmos; properly, a case (to keep mouthpieces of wind-instruments in) i.e. (by extension) a casket or (specially) purse -- bag.
KJV: This he said, not that he cared for the poor; but because he was a thief, and had the bag, and bare what was put therein.
NASB: Now he said this, not because he was concerned about the poor, but because he was a thief, and as he had the money box, he used to pilfer what was put into it.
KJV: For some of them thought, because Judas had the bag, that Jesus had said unto him, Buy those things that we have need of against the feast; or, that he should give something to the poor.
NASB: For some were supposing, because Judas had the money box, that Jesus was saying to him, "Buy the things we have need of for the feast"; or else, that he should give something to the poor.