The traveler is ALWAYS responsible for GRATUITIES and any other on board expenses. If you select the minimum accommodations offered, then there is no additional charge except for taxes and fees. The holiday list includes, Christmas, New Years, Thanksgiving, July 3, Memorial Day, Easter, Holy Week, Labor day, President's day. This cruise is ANY up to 8 night sailing as long as it is not over any holiday. The cruise accommodation depends on the casino program level. Then there is the PRIME few cruise that one earns because of points earned over a one year period. Some people get lots of them, and others do not.
It may be for an interior or other accommodations, may be for a BOGO, may be $$ off or may be for what they call 'special casino pricing'. This offer may also include a value you can apply to a cruise not listed. The next is a promotion free cruise award emailed/mailed by the casino for a variety of sailings, or maybe just one sailing. I cannot offer any other info on this type of free cruise as we have never obtained the necessary points. Some number of points ON ONE CRUISE gets you a certificate for a specific type of accommodations and on specific sailings. One is a few cruise certificate by gambling on ONE cruise. There are several types of free cruises offered by the casino, and some have different rules.