How do I get to Surat Thani by car from Bangkok? Cheapest Air Tickets from Bangkok to Koh Samui?

I have driven from Bangkok to Koh Samui it's about a 10 hours trip. I have seen people go by taxi but I don't know what it would cost. Direct flights from Bangkok to Samui aren't really cheap. Only Bangkok Air and Thai Air flies to Samui. You could take air asia to Surat Thani and a bus to the ferry for Koh Samui, that would be a cheaper then flying to Koh Samu. If you don't want to fly you can take the train and then a bus to the pier, or just take a bus direct to the pier from Bangkok. Bus or tran will be overnight trip of about 12 hours.