Had a customer call me asking for a source for some aluminum to make some mold cooling plates. I knew he couldn't buy it for the same price I do even from my vendors, and I told him who my vendors are. Coast and Midwest. With a very strong preference for Coast personally, but Midwest ships... when ever they are darned good and ready anyway.
I told him I would just throw a piece of bar on the saw and cut some for him if he wanted. At a fair markup of course. I know I can sell the aluminum I stock WAY less than any of the online vendors and insultingly less than local metal yards and still make a good profit because I buy multiple 12' pieces at a time. From a few hundred pounds to several hundred pounds post of the time.
He told me what we wanted and I did the math several times, and I was only paying a couple dollars less per piece than he found online. It didn't make sense. I buy hundreds of pounds of 12 foot bars. Well, I agreed to sell him what he needed in a flat rate box, match the price, and sent him an invoice. Then I realized I was doing calculations based on price per foot, and he wanted 4 inch long pieces (6 x 4 cut from 6 inch wide stock). Oops. LOL. I called him and said "DON'T PAY THAT INVOICE." Now we are both much happier.
He paid the new invoice before I finished typing this post.