Taxi Rates

I suspect that the high price for Troncones is because the driver taking you there isn't allowed to pick up a fare for the trip back to Zihua; thus, they charge you for their trip back with no fare.

Back in the early 90s we took a taxi from Ixtapa to Troncones. We agreed on $25 US......for the return trip. (Can't recall what the $Can equivalent was). The deal was that the taxi would come back to pick us up at 3 pm. Trusting fellow that I was, I gave the driver the full $25 when he dropped us off in Troncones. The possibility that he wouldn't show up never entered my mind: promptly at 3 pm, there he was. I gave him a reasonable tip when we got back to Ixtapa.
These days, as has been noted, non-local taxis usually won't risk picking up fares when out of their area.