Capacitor values for use with 78xx voltage regulators
Your data sheet probably says that neither capacitor is actually required if the regulator is close to the input filter capacitor. 

What is optimal is a function of how quickly and how much the output current changes as well as the input filter capacitor distance and size. 

If it's a digital circuit, something like a 1uF/10V X7R capacitor on the output and a 47uF/50V electrolytic on the input will work just fine. They're often specified with 0.33uF on the input and 0.1uF on the output but there is nothing magic about those values, and the 7805 is unconditionally stable regardless of output capacitor ESR, so more capacitance means better transient load response. Ceramic capacitors much larger than 0.1uF used to be expensive, but no longer (the 7805 is a 1970s era design).