The first day I to went was practice. It was free to get in and one man and his dog showed up to watch. I got the train to Nilai, which took an hour, I then planned to catch a bus to the circuit as the Sepang website told me. Unfortunately there were no buses running to the circuit so I caught the bus to the airport, this took another hour. When I arrived I asked for the bus to the circuit and was told that no buses were running and I would have to catch a taxi. The taxi cost me RM38 (about 5 pounds) not an arm and a leg but the previous two hours of travel had cost me RM6. On the way back I stood at the side of the motorway with another spectator and attempted to flag down coaches bound for KL. We stood there for an hour unable to get a coach to stop. A plethora of taxis did attempt to come to our aid. It doesn't matter where you are in Malaysia, you can be minding your own business strolling down a street, when you will hear the light toot of a horn announcing that a taxi is ready and raring to take you wherever you may wish. Whilst waiting at the side of the motorway we negotiated with several drivers. They would propose outlandish charges of RM70 and we would counter with RM10. Eventually we found a driver who we haggled down to RM15. We got to the airport and then jumped on a coach to KL, it only cost RM10.
The next day was qualifying. I caught a coach to the airport and then managed to persuade the airport bus driver to go via the circuit (this was after I refused to get off the bus until I was taken there). When I left the circuit the extra spectators for qualifying had prompted taxis to pull up outside the entrance. "You want taxi sir?", "How much to the airport?", "50 Ringgits", ""I paid 15 yesterday", "No, no sir 40 Ringgits". I had this conversation with a number of drivers and carried on walking to the motorway. I was met with the toots of horns from taxis. They would offer me a price, and my new tactic became shutting the door on them after a bid I didn't like. A couple of drivers pulled up and after I rejected them they reversed along the hard shoulder to the previous turnoff. I was beginning to wonder whether my confidence in getting a low price was misplaced when a taxi pulled up and offered me the fare of RM10, I didn't bother haggling.
On race day I managed to get the airport coach to drop me off at the circuit. There was a decent turnout of spectators, probably around 5,000 people. At the end of the day I wandered out of the circuit and found drivers who weren't interested in taking me to the airport, they wanted the big fares to KL. I continued my stroll toward the motorway when a driver pulled up next to me and offered me RM40 to the airport, I said no 10, and shut the door. He opened the door and offered 30, I said no and shut the door. He opened the door and offered 20, I said no and I would accept 15. He said no so I walked off. I could hear him yelling in the background and then he pulled up next to me, "Jump in sir, I take you airport for 15 Ringgits". I should have gone lower.
I would recommend visiting Sepang for a race. It is a beautiful circuit, very modern, with great views of the track. It also gives you a crash course in bartering.