I want to travel to Singapore

Unless you're traveling from Malaysia, you'd better hope your bus can swim. Singapore is on an island.

You may need to go by plane. Plenty around!

There is water between Singapore and Malaysia. There are ferries that you can take. While you are in Singapore, don't miss a) botanical garden, b) Raffles Hotel's long bar, and that's where the Singapore Sling was invented (it's the only place in Singapore where you can throw peanut shells on the ground), c) Sentosa Island, d) Chinatown and Malaytown, and e) shopping.

Bus fare is $1 or $2 depending on distance. They also have prepaid cards.
Trivia: the land between the airport and downtown is landfill.