there are so many people inviting me to different trading groups. how do i know that these are not scams? thanks.
I guess if you have to pay to be a part of the trading group you have to research about the group further before joining. I’m not saying that all paid trading groups are scams but just be careful. 
Hmmm. 
I’ve never really thought of joining trading groups because I’m kind of scared I won’t be able to add any value there. 
Haha. But yeah. I agree with @CoinLady. One good way to find out is when they start (or eventually) ask you to pay for stuff. 