WordNet sense 1 (a homeless boy who has been abandoned and roams the streets):

gamin, street arab

WordNet sense 2 (an advertisement (usually printed on a page or in a leaflet) intended for wide distribution):

bill, broadsheet, broadside, circular, flier, flyer, handbill

WordNet sense 3 (thrown away):

cast-off, discarded, thrown-away

WordNet sense 4 (not wanted; not needed):

unwanted

WordNet sense 5 (designed to be disposed of after use):

disposable