1998 Saturn SL just won't start anymore.

Assuming it will turn over ('cranks"), my bet would be the crank sensor has failed, and it is not to difficult to change if you can get the car in the air high enough to get fully under it. The sensor is located just above the starter, on the side of the engine closest to the firewall. It is held in place by one bolt, and you will need to remove the electrical connector to remove it. a new one is usually less than $50, and almost any auto repair shop should be able to replace it for less than $125.