What field will you invest in if you have 1000 USD ?

But he wants 100 times of ROI in 3 (three) months :)

Most people make the mistake between speculating and investing.

1- Speculation is a game. Hien Duy is joking of course, because if it was that easy, he would not be spending all his money traveling around, no need to work. Networking would be thousands of people queuing up to meet him. You can do that at the casino and bet 1$ black/Red, you lose you double, you win you do the same with the 1$ win, so no lose, only gains... of course there is a catch and the casino have figured out already... more on that, just email me.

2- Investment is a full time job and attached knowledge and skills. Warren Buffett started at age 16, successful till now age 82. But so many go bankrupt for 1 Buffett. It takes time to get those skills
2bis- Investing in a coffee shop is not investing, it is working, it is starting a new business so you will need to get the skills (or hire them...) with no guarantee because you are new in the business. But if you decide to be partner and give money to a friend/wife to run the business you become an investor, so make sure you have the skills of 2-

NB. 1000$ or 1Mn$ is the same process if you know how to make a good ROI with low risk investing 1,000$, and you can show it is no luck, using the same skills with 1,000,000$ is the same. You've got the skills!

Tôi rất mê ý tưởng của Anh nhưng Tôi nghĩ Anh có thể đổi với giá đắt không?

I'm really starting interested in this, I'm also want to invest in something with an amount like this, but I dont know what to do now :)

you can invest on gold market or forex. legally but you must have a lot of luck. :D