paper is inexpensive in free
paper_currency is free_sheet. waste_paper is paper. paper is limited_resource. plastic_and_cardboard is both_inexpensive_materials. sheet_of_paper is free_sheet. free_pornography is free_stuff. group_of_paper_currency is group_of_free_sheets. art_paper is paper. paper is one_of_things. freeware is free_stuff.