Albert Barnes on Matthew 26:8

They had indignation. John says that Judas expressed indignation. Probably some of the others felt indignation, but Judas only gave vent to his feelings. The reason why Judas was indignant was that he had the bag, (Jn 12:6;) i.e., the purse, or repository of articles given to the disciples and to the Saviour. He was a thief; and was in the habit, it seems, of taking out and putting to his own use what was put in for them in common. The leading trait of Judas' character was avarice; and no opportunity was suffered to pass without attempting by base and wicked means, to make money. In his example, an avaricious man may learn the true nature and the effect of that grovelling and wicked passion. It led him to commit the enormous crime of betraying his Lord to death; and it will always lead its possessor to guilt. No small part of the sins of the men of the world can be traced to avarice; and many and many a time since the days of Judas has the Lord Jesus been betrayed among his professed friends by the same base propensity.

Is this waste. This loss or destruction of property. They could see no use in it, and they therefore supposed it was lost.