Is there really much profit from selling a $.10 screw that the average person might need once or twice a year when they buy some unassembled product that is mis

Is there really much profit from selling a $.10 screw that the average person might need once or twice a year when they buy some unassembled product that is missing parts? I assume people who would buy bulk don't need an app to tell them what to buy. Or do they charge an insane markup for these one-offs? Personally, I love an excuse to go to an old fashioned Ace Hardware store and ask a real person for help.