I'll add a little more on the subject of cheap. Here's what I've spent on EDIS parts:
EDIS6 module = $6
VR Sensor = $3
36-1 Wheel = $4
EDIS6 coil pack = $8
EDIS6 wires = $6
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Total = about $27
This was from my wonderful local pick'n'pull. They have one price for each basic category of part and it is almost always in your favor.
I made a poor man’s test bench to make sure everything worked. I mounted the wheel to a electric motor, put the VR sensor in a chemistry stand above the wheel, connected the module to the VR, coil pack and battery, and wrapped bare copper wire around the base of 6 spark plugs to ground them. This let me toy with the setup and get comfortable with the wiring, all for free on my workbench.
The really great thing was being able to test it on the car without disturbing the existing ignition. I mounted the wheel and the VR and just left everything else lying on the floor. I would switch between EDIS and stock just by changing spark plug wires. This can be done because EDIS will run 10 degrees adv. without additional input.
I was able to idle on the first start with MS2 and EDIS, partly because of the easy pretesting.
If you like the idea of EDIS, don't let cost concern you. It can be done cheap.