All are NOT equal. Two things I want to say right off the top:
1) There can be only one
skipper on board--that's you, you have
legal and moral responsibility for the welfare of vessel and crew...no matter in what way they may let you down.
2) People vary considerably in how long they can maintain a useful watch--and in how they cooperate with the skipper's instructions to put the mobile
phone in airplane mode and not look at it. [Happened to a singlehanded friend of ours. Very bad. Also refused to tie a cleat hitch his way -- different ships, different long splices.] You gotta sleep sometime, and your welfare, and that of the vessel are in charge of whoever's on watch. Choose well your crew. You need people who can tolerate lack of visual stimulation, and who will follow instruction.
What is fair? Well, we would never charge a friend to take them sailing and we would gladly feed them. This said, for
family members, we have paid their airfare when they couldn't easily afford it. If you have friends for the long legs,
who are sailors already, they will be worth their weight in gold. If they are not sailors and you have to train them, good luck with that. What you have to deal with are strong minded people who have confidence in their own point of view, whether or not they'll do what you say is really up to them, and they are able to let you down. That said, I would say there are people out there for whom having to pay you for the experience might make them more cooperative--may or may not be the kinds of folks you are looking for.
Offer what YOU think is fair, not the consensus from a forum.
Forums have many people with ideas different from yours. The responsibilities are all yours, so you decide in whatever manner seems best to YOU. If you let others make the decision for you, you may be unhappy with it in the long run. Me, I'd stay flexible. I would ask for help, both monetarily and with transport to the boat if I needed it. They are free to say no. But keep the negotiations up front, don't spring $$ charges on folks who can't help.
Ann