My friend and I flew into SIN on our way to the Prentian Islands April 2000. The cheapest option was to fly through KUL to North Eastern Malaysia.
I do not remember the price, but tix out of Johor Baru were much, much cheper than out of SIN and first class was just a few dollars more. Malyasian Airlines has a bus from SIN to Johor Baru that went from airport to airport for a small fee. Also with the first class tix it permits lounge access in both JB and KL.
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The world is a book, and for those who do not travel, read only a page.
-Saint Augustine