No personal experience, but if you want the same car to take you there, wait and bring you back, it is somewhere in the range of $300 or more.
Here are three links with bunch of options, read and pick up the one suits you
https://www.busonlineticket.com/book...nd-bus-tickets
https://www.sgmytaxi.com/how-to-go-t...m-singapore/#1
https://www.legoland.com.my/planning...w-to-get-here/