It would be good to have sub forums for US and non-US investment topics - while the philosophy is applicable anywhere, the details are highly specific to individual countries. For example, all the talk about 401k, roth, IRA is all great if that's your environment, but is meaningless to me in Australia with an environment of superannuation, salary sacrifice, and franked dividends. I looked briefly at setting up an investment holding company in Singapore, and it looks like it has a quite different set of rules, and lower tax rates dropping the incentives.
As to low cost investment options, it wouldn't surprise me if you can access them from Singapore. I know a number of low cost options trade on the ASX, and I suspect you might find the same on the Singapore bourse. A quick web search shows that Vanguard (one of the large indexing providers in the US) operates in Singapore -
https://www.vanguard.sg but I could only find information for institutional investors rather than retail investors. Maybe start by getting in touch with them?
Good luck!