If we take the bus from Catania to Agrigento are taxi's easy to come by and reasonable prices? Vrs paying for a car for a family of 5 to drive from Catania to Agrigento and back.
A family of 5 would need a minivan, which are very expensive to rent. So a taxi from the bus station to the valley of the temples is likely cheaper. I’m sure there are city buses also from the station to archeological park, which is a bit out of town.
Here is a list telephone of all taxi drivers in Agrigento. It doesn’t appear they are part of a cooperative company like in major cities, so there is not a central number for a taxi company. They are all mobile phones of the individual drivers, you can tell they are mobile phones because they are all numbers with area codes starting with 3 (all mobile phones in Italy have an area code starting with 3, regardless of where in Italy the subscriber resides). You need to dial +39 before the listed number if you are calling from a U.S. phone. They probably have the same number as Whatsapp.
https://www.agrigentonotizie.it/guida/trasporti/numeri-utili-taxi-agrigento.html