It's really quite simple. Get a group of friends, relatives, co-workers, or acquaintances together and plan a group cruise. Sixteen people booked into 8 double rooms qualifies as a group. In addition to discounted fares and assorted perks that the cruise lines love to lavish on groups, one of each 16 beds is free. (You pay only taxes and government fees.) If you prefer, the discount can be spread among all of the travelers to give each of them a better deal.

Sound good? Let's start planning that group cruise. Maybe you can sail for (almost) free.