~snip~
Investing or trading aren't what op is looking for since they require initial investments while he wants to invest nothing and gain something which implies that he is looking for free money basically.
It's hard to use sites to make free money these days, and it's different from a few years ago. That is why I suggest he invest or trade to make money. But of course, they have to have money to start with. But we know that freebitco provides a faucet facility that he can use if he wants to start for free without needing money. But he must realize that playing the faucet really takes time until he can collect a lot of satoshi. He could also try gambling there, but that is not recommended. But that will be up to him.