Last month I was in Singapore (for 6 hours) and then Jakarta and Bali. In the SIN airport I bought two adaptors, one for US-Singapore and one for US-Indonesia for US$4 each. Definitely different. The Singapore adaptor was fine.

The Indonesian adaptor had the proper 2 prongs, but it wasn't round, and didn't fit the sockets. I borrowed the the proper adaptors from the Jakarta hotels at no cost.

In Bali, I went to an electrical supply store and bought a very small adaptor for less than US$1.

I then saw more expensive adaptors being sold on the street for US$5.

BTW, internet access in Jakarta is much more difficult than in other parts of the world. Hotel internet access was expensive and Internet Cafes were sparse.