Q: I booked a cabin on a cruise that was advertised for $700, but when my agency billed me, the cost was $850. When I asked, I was told that because I’d be alone in the cabin, I had to pay a single supplement. Just because I’m single, why should I have to pay that extra charge?

Frieda M., Queens NY

A: Single supplement charges are the usual practice for a valid reason, at least for the cruise line’s balance sheet. Cabins are intended to have two passengers, and if you had signed up to cruise with a companion, the cabin would’ve brought in $1,400. The cruise line partially makes up for what it considers a loss by charging singles another $150, which is somewhat reasonable. Some cruise lines charge the equivalent of two full fares for cabins with just one single occupying it.

Unless you value total privacy on the cruise, you may ask your travel agency if the cruise line lists any other singles on the same sailing who are willing to share cabins. This is not unusual on cruises, especially those that cater to singles or are advertised as singles only trips.