What the daily rate includes, and what it does not
The price on a listing is the rate for one day on the water. What comes with it is stated on the same page: base equipment, bedding, and the services the owner chose to include.
Things that usually cost extra are listed right next to the price — a skipper, fuel beyond the day allowance, the final cleaning, or a tourist tax in some marinas. Read that block before you request the dates, because it is the part of the listing that decides the final amount.