Im a student age 21. Currently i only earn 200 from my part time job. How can i start to invest?

I answered a similar question on another thread! I would recommend saving up for your emergency fund first. Assuming you already have that emergency fund in place and any excess is for investments:
With $0: Start investing in your own financial knowledge:

1. Read forums for financial knowledge. SeekingAlpha, MotleyFool, Seedly etc.
2. Read quality news: Financial Times etc (subject to paywall)
3. Read books on both Value Investing and investments in general. Assuming you are based in Singapore, our National Library is a good place to start.

With $100, if you really want to start investing with small sums: You can start investing with as little as $100 with Monthly Investment Plans for a start. Some to look at are:

1. POSB Invest Saver
2. OCBC Blue Chip Investment Plan (BCIP)
3. Maybank Kim Eng Monthly Investment Plan
4. Phillip Share Builder Plan

Hi,

You should not start to invest first. You should save up more money.

Make sure you save up at least 6 month of monthly expense as an emergency fund. Anything excess then you have the right to invest in the market.