1991 Subaru Loyale Question: What are the main causes of a Subaru not starting

I was driving one evening, and the car just stop running in the middle of gassing. I pushed the car to the side of the road and tried to start it. The car is cranking but will not cut on. I had a friend hook jumper cable to the car and tried to start it, no dice. I checked all the fuses and none appear to be bad, no breakage on any of them. When I turn the key without turning on the car, you hear a low buzz from the fuel pump, so I'm assuming this isn't an issue, though a neighbor said it still may be the pump. Any answers will be appreciated. I'm trying to fix this myself for financial reasons.