Does a 1994 Geo Prizm have a timing belt or a timing chain?
1994 Geo Prizm has a timing belt.
I can't say for sure, but I have a 2001 Prizm and called some mechanics to look into having the belt changed, and they told me I didn't need to because it has a chain. According to the repair manual from 1993 through 1997 the Prizm used a timing belt and was an interference engine. From 1998 until end of production the Prizm used a timing chain. same with its mechanical twin, the Toyota corolla.
The Prizm has a timing CHAIN, not belt. The timing chain does not get replaced on a scheduled interval. It should never need to be replaced. The serpentine belt, however, does need to be replaced. Inspect the belt for cracks and glazing, and replace. It is not a difficult DIY job. It is easiest to do it from under the car, after removing the splash pan.