Besides RepRap kits they offer parts like Assembled Modified Wildseyed Simple Hot End for 3mm filament
Assembled Modified Wildseyed Simple Hot End for 3mm filament. The original Wildseyed Simple Hot End is easy to make with relatively easy to obtain and machine parts (although Teflon rod is not so simple to obtain on the east coast). We use nichrome wire for heating instead of the heat sink and resistor in the original hot end, as it is much more compact. We insulate the wire with furnace cement, and bake it to cure it. You will need to drill two 1/8” holes to secure the hot end to the oak mount. The oak mount is our contribution to the Wildseyed Simple. It isn’t in any danger of ignition as it does not touch the metal of the hot end; the wood serves as a simple mechanical link between the Teflon rod at the top of the hot end and the cold end of the extruder. The hot end comes with short lengths of Teflon wire attached, which can be connected to your wiring harness with ordinary wire.