Trying to find cheapest way from kuala lumpur to koh samui by other means

They're on different coasts so forget boat all the way.
Train to Butterworth then to ST then ferry across.
Bus/ train to.Butterworth then mini van from Penang to ST then ferry.

Check Berjaya Air - SZB(SubangAirport) to Samui for as little as $64us on selected days. But be aware of their crap free check in luggage allowance of only 10KG.

Trying to find cheapest way from kuala lumpur to koh samui by other means

hey everyone, i've tried getting tickets from firefly but they're still too expensive
is there other means of travelling up there?

Yes - walking. It's the cheapest/

If that doesnt appeal to you, change your destination to Phuket and fly direct with Air Asia. Samui is like Miami now anyway, Phuket can get better weather and more diverse. Check it out..
welcome to the Isthmus of Kra.

if you really want to go cheap, you can hitchhike in malaysia and get a bus in thailand. i never found too much luck hitching in thailand except in the north.