SIM card costs for tourists and how to get it easily in Singapore
As a tourist you can get a SIM card upon arrival at the Changi airport. Once you get your luggage and leave the secure area, you'll see multiple booths advertising these
Cost varies slightly by vendor. To give you a sense, StarHub (one of the 3 major telecoms here) has a package for 100GB of data for 12 days for $32 SGD, and this package also includes:
3000 minutes local calls
3GB of roaming data in a bunch of other countries for 30 days from activation. This is fantastic if you're going to visit neighboring countries after Singapore because you don't have to get another SIM cards there:
You can purchase it by credit card so no need to have cash SGD at the airport for this, and it takes less than 5 minutes to set up (they will do it for you actually)
I highly recommend getting one because it helps very much with navigating around Singapore (for using public transportation navigation apps like CityMapper to calling taxi with Grab). And 100GB is more than enough for everything you will possibly need