don't forget the so called conveince factor[way do you think we now suffer the con store selling gas instead of a service station,it might be handy but the markup for most non fuel items is crazy,gas price another issue].[price not real but gives idea]10$ for 20 asprin in pocket sized metal or plastic box or 2$ for large unhandy bottle of 200[even through you could break it down youself for pocket pack]   most stupidly lazy but flush pocket people go for 20 at 10.