30-40 USD sounds incredibly cheap. I would expect a trip from one end of Kyoto to another to cost that much or close already.
I've made the trip about a dozen times. MK SkyGate Shuttle (formerly Yasaka)
Normal taxi is forbidden. I've heard of someone's friend having to pay 30 man (yes, more than 3 times the plane ticket) to go from airport to home in a remote prefecture because of that countermeasure.