King Camp Gillette, a late nineteenth century American businessman, invented the disposable razor. Although he initially tried to make money with both the razors and blades, he soon realised the more razors there were in the market, the more premium priced blades he would sell. The sales model was born, sell razors at a loss, then make money from the captive audience buying blades.
The business model is widely used today. Inkjet printers are a classic example: Complex printers are sold well below cost because the manufacturers know we will buy their cartridges during it’s life at a hugely inflated price.