Even if you are not a Marina Bay Sands guest, you ...

Even if you are not a Marina Bay Sands guest, you can go to the top floor if you pay the entrance fee.
The admission fee includes a drink, and you can go home after drinking only one cup.
However, not all drinks can be ordered with an admission ticket, and some drinks cost an additional fee.
I strongly recommend it as a place you want to visit once in Singapore.