Wow, this is one of the most unusual questions we have received here at Mozilla support. We generally answer questions about Firefox, and sometimes your computer.

Could I suggest you look up the brand and model number of your coffee maker and then search that online until you find the manufacturer's website? They would be happy to sell you filters, I'm sure, or you can find out the product number of the filters and look for them at other retailers to see whether they're cheaper there.

Good luck!

Locking this thread because it is not a question about Firefox.