If it is something that is considered as "too good to be true" then that's most likely a scam. Signal groups are not reliable source of investing though, but they can somehow help you understand the fundamentals and technical analysis as you all can share knowledge and update regarding the specific coin within the group, but most importantly it is not something that you will pay for, it is FREE of charge. Those signal group claiming to be the best in that field and collecting registration fees, they are most of the time run by by group of scammers.
So, my advice is that - dont just follow what the group has said but you should always DYOR.