1990 Audi 100 ignition problem

I need help on a 1990 100. I bought car to save from being salvaged. Car turns over is getting fuel. But I'm missing spark somewhere in the distributor. I have spark from the coil. But none at the spark plug. Wonder if someone could help with troubleshooting and give some Ideas on how to test the components. Don't want to spend alot. Vehicles only worth 1500 or so.

Brian