Actually the cost may be a little over $1.00, depending where you get the parts. The parts list and costs are:

Disclaimer
This article documents modifications to the X-10 WS467/477 wall switch module. Opening this module will void your warranty. And more importantly, removing this module from its case will expose you to the possibility of electrocution. The modules connect DIRECTLY to the line voltage (120 Volts). When there are out of their protective plastic cases, they can kill you if connected to the wall socket and you touch the wrong thing. Do NOT connect this module to the wall when out of the case! Be very careful! Also, there is a possibility of the module catching fire if wired incorrectly and plugged in. Proceed at you own Risk! I take no responsibility if you electrocute yourself or cause a fire.

This modification does add a neutral wire to the module. It is required to function correctly.

I used 24 gage hook-up wire for this project, unless otherwise indicated. I found that anything bigger would not fit in the smaller holes in the PC board.

Remove the back of the case by lifting up the 4 corners and fishing out the blue and black wires.

Remove the screw, washer, and nut from the triac and save.

Slip a knife or thin small screwdriver in between the case and the circuit board and remove. Be carefull after removing the board not to disturb the dials. They can be a little difficult to get back in correctly. Set the 2 case parts aside in a safe place so that you will not bump them and spill the 2 dials.

Remove the parts shown in the following photo. The parts are: R9(1K), R8 (39 ohm), R3 (330K), diodes D7, D11. Save the 1k and the 330k resistor for use later. These parts are connected the gate of the triac. We want all the parts (ie these parts) removed so that the gate can be connected to the opto isolator chip. Remove the Choke
After removing the marked components, we need to make a slight modification to the board. Drill out the hole that R3 was originally in. I used a 1/16" bit. Solder the saved 330K resistor in the hole that the choke was originally in. Do not connect the other end of the 330K at this time. We are going to be hot-gluing the opto-isolator to the PC board, The hot-melt glue does not stick very well to the slick surface of the PC board. Use a small piece (about 1 in square) of medium grit sandpaper to remove the gloss as show in the photo below. If you use a very sharp drill bit, you should have no trouble with the hole enlargement. Drill from the component side.
Turn the board over and solder a jumper in the positon show in the next photo. This allows the board to work without the slide switch on the front.
Now we hotmelt glue the MOC3042 to the board. The position is somewhat important. Use the location shown in the next photo. Make sure that pin 1 is in the correct position.
Let's go ahead and finish connecting the 330K resistor. Clip off the lead to 1/4 inch and solder a pice of 24 guage hook up wire to it. Connect the other end of the wire to the original 330K resistor hole (the one that we did not drill out). See following photo.
Now we are ready to begin the wiring of the MOC3042. Since there are no extra holes in the PC board that we can use for the 1k resistor and the 22mfd cap, we have to mount them on the MOC3042. Start by cutting the leads of the cap to about 3/4 in. Make a small loop at the end of the negative lead and attach it to Pin 2 of the MOC3042. Take the saved 1k resistor, make a loop in one end and attach it to Pin 1 of the MOC3042. Now take the free lead from the cap and the free lead from the resistor and solder together
Now connect on end of a wire to Pin 2 of the MOC3042 and connect the other end to the hole fomerlly occupied by R8. Use the hole closest to the edge of the board. This will connect the opto-isolator to the collector of the gate drive transistor. Connect one end of another wire to the junction of the 1k resistor and the 22mfd cap. Connect the other end to the left hand hole of R3. This picks up +15v for the opto-isolator
It is now time to connect the rest of the opto-isolator. Insert a 22 ohm 1/2 watt resistor into the hole formally occupied by one lead of the choke. Connect the other end of the resistor to Pin 6 of the opto-isolator. Connect one end of a wire to Pin 4 of the opto-isolator and connect the other end to the right-hand hole of R3. This connects the gate control section of the circuit.
All that remains is to move the load wire. Clip the blue wire about 1 inch from the end towards the board. Replace this wire with a white piece of hookup wire. The size does not matter much here. There is no load current on this wire. Just a small current for the board. I used a piece of 22 guage stranded wire. Strip the end of the blue wire and insert it into the hole drilled out earlier. This is the hole formerly occupied by the 330K resistor. This now reconnects the load wire back to MT2 of the triac. Willis's article left the original blue wire in place which now becomes the neutral wire. You can do the same here. If you do not want to cut the blue wire, just solder a new wire (this wire is the load wire, use 18-20 guage) in the drilled-out hole. The new wire is now the load (not the blue wire) and the blue wire is now the neutral. I like to keep the proper colors for hooking it up, so I cut and replace the wire so that I can have black for hot, white for neutral, and blue for load. If you do cut the blue wire and attach a new one, the connection has to be insulated. This wire is connected directly to the neutral side of the line voltage. I use heat shrink tubing. Make sure that it cannot short out.
That is it! No case modifications are required. Slip the PC board back into the case being very careful not to get the wheels out of their place. Reinstall the screw, washer, & nut to the heatsink/Triac. Route the 3 wires back through the strain relief and snap the case shut. You might have to play with the 3 wires to get the case to close properly.

 And finally, heed the label max power rating. The original wattage rating on the label is 500 watts (approximately 4.2 amps). The circuit components will handle more that the 4.2 amp current, but the heatsink will not. Stay within the 500 watt rating.

Old Circuit	New Circuit