How much should I expect to pay for a taxi from Cebu for 3.5 hours?

These days, 6,000 to 8,000 is about right. Don't be stingy. Gas is expensive now.

I've seen a lot of people get overcharged. Ask a taxi driver who works at a motel. If you pay the driver a daily rate and cover the gas, he'll stay with you exclusively all day. He'll take you anywhere, go to karaoke and sing with you, drink with you, and show you everything you want to see. When I went to Manila, an American who had been abandoned by the family he met said he was leaving the Philippines early. I introduced him to a decent driver, and he hired him by the day. He said he extended his stay by several weeks and had a great time.

There are Ceres buses that go north or south for cheap. The luggage compartment is huge too. Take a taxi to the Ceres terminal.