With such grups you are chaising tail. and only leader of pump is getting hard cash rest most likely will sponsor his earnngs. You will most likely loose money there.
Avoid the risk of losing your money. There should be testimonials to prove this site is working properly or not. Being cautious is better than carelessness. No success without a good learning process. Just enjoy the process and the results certainly will not disappoint. 
Pump group isnt illegal. Some people dont like it from bad experience.
Yes, it isn't illegal, and it's widely spread, but greed makes such groups always fail. I have been into one, but didn't really work out you can't resist a free market.