1. Some? ?companies? ?advertise:? ?"We? ?deal? ?in? ?high? ?volume? ?and? ?pass? ?our? ?savings? ?on? ?to? ?you? ?in? ?the form? ?of? ?lower? ?prices."? ?How? ?could? ?this? ?be?
2. Many? ?people? ?search? ?out? ?and? ?purchase? ?"bargains"? ?at? ?garage? ?and? ?yard? ?sales.? ?What? ?are some? ?implicit? ?costs? ?associated? ?with? ?this? ?type? ?of? ?shopping?
3. Is? ?the? ?"best"? ?quantity? ?of? ?workers? ?to? ?hire? ?where? ?the? ?marginal? ?productivity? ?of? ?the? ?last worker? ?employed? ?is? ?the? ?greatest? ?(which? ?implies? ?an? ?output? ?level? ?in? ?which? ?the? ?marginal? ?cost of? ?producing? ?additional? ?units? ?is? ?the? ?cheapest)?