There are a number of sellers advertising Lexmark 50 (Black) and Lexmark 20 (Tricolor) cartridges that are actually #48 (black) and #19 (color). These are the cartridges that Lexmark shipped with new printers (Have you noticed that most Lexmark printers are being sold without the cartridges? That's so sellers can market them separately - the Lexmark cartridges are expensive because the print head is built into the cartridge.) These cartridges DO NOT contain the same amount of ink that the retail #50 and #20 contain - they contain just enough ink (barely) to print a few pages. In fact, Lexmark received so many complaints from consumers about these "light" cartridges not working at all (there was so little ink in them that they dried up sitting on store shelves) that stores had to accept them as returns. Now do you see why these are showing up on eBay? Many sellers (including "power sellers") show stock photos of #50 and #20 cartridges, but in the (very) small print they might be identified as the short-fill cartridges. Or maybe not. If the inner Mylar wrapper reads "when installing, select cartridge 48 (or 19); when purchasing a new cartridge, purchase #50 (or #20). This is so the software ink level meter will (more or less) reflect the amount of ink left in the cartridge. ASK THE SELLER - are his/her cartridges 50 and 20, or 48 and 19. Then, if you're lied to, file fraud complaints with eBay and/or PayPal. And read the auction description carefully - all they have to do is bury those bad numbers somewhere in the small print, and you're screwed.