We have a Brother MFC-L3770 laser with cartridges for at least $80 each at Office Depot. Who wants to spend $320, almost the cost of a new printer, on Brother cartridges. I was excited to find them for the price. Well, they worked temporarily. Our printer suddenly stopped printing and we kept getting "replace toner" messages after the new ones had worked for a while. The Office Depot rep said this is most likely because I didn't use branded cartridges. After replacing these cheap cartridges with real "Brother" everything worked again. I found them on Walmart.com for about $280 but my goodness! Apparently, printers can eventually realize that the inks are in fact incompatible. Now we have cartridges that we cannot use.