Currently the Champion 3X plug,Champion part number 429 sells for 44.95 on Amazon and most auto parts stores. They are OEM parts for the Model A Ford. If you keep your eyes open every now and then you can find them in swap meets and antique stores. I found these at a local swap meet and bought them for 5 dollars a piece. While many use the Champion W16Y or the Motorcraft TT10 plug for the Model A motor nothing runs as good as the original 3X plug. With just a little bit of time and attention these three cleaned up like new and with the one plug I already had made a nice set for my 1931 Tudor.