Mark wants to show his readers that those present were more concerned about money. This can be stated in active form. Alternate translation: "We could have sold this perfume" or "She could have sold this perfume" (See: [[rc://en/ta/man/translate/figs-activepassive]])
The phrase "the poor" refers to poor people. This refers to giving the money from the sale of the perfume to the poor. Alternate translation: "the money given to poor people" (See: [[rc://en/ta/man/translate/figs-ellipsis]] and [[rc://en/ta/man/translate/figs-nominaladj]])