When doing a trip outside I generally buy everything including tackle, bait, food and fuel up the boat when we come home then split the lot by however many have gone on the trip. Deckies come back and help clean the boat, clean fish and drink beer. If they don't it'll be a long time before they get another trip. But everybody always does. Every body is aware of the expectations before we go.
If we are just going for a fish up the creek or a joy ride out in the bay don't usually worry about money as it doesn't add up to a lot. Don't include service costs for the boat I figure that is just part of owning a boat. But would understand if people did put a small amount on as it costs a lot of money to maintain a boat in safe working condition.