Apple has updated the iTunes App Store and Mac App Stores to show Sing$ instead of US$ previously. Apps now start at S$1.28 rather than the US$0.99 we are familiar with. However, the conversion rate varies, depending on apps.
For example the recently launched Launch Center Pro is selling at US$2.99 while it is listed at S$3.98 (US$1=S$1.33), while Pages is selling at US$9.99 and S$12.98 (US$1=$1.299).
But hey, at least you know now how much you are forking out for all the apps you are buying.