"The skipper don`t pay in, but he consume also."
Yes, well, if it was a straight deal you should bear in mind the skipper may not be paying but he's contributing the boat. That's how it works when you take friends sailing, they often take on some of the expenses because the owner is making the big ones.
But the deals you see to "share expenses" are something to look at very cautiously. If someone is advertising commercially and taking on strangers--that's commercial and they're trying to dodge the regulations requiring a commercial license, a captain's license, business license, often dodging insurance regulations as well.
If you are being told to pay, pay a sailing school or other BUSINESS that is not trying to play games with regulations. If they are trying to cheat...but of course, they're trying to cheat someone else, they'd never cheat on you, would they?