Meclizine is the generic name for Bonine and a fraction of the cost. If not on the pharmacy shelf, ask for it at the counter. I won't travel without it.
I'm very prone to motion sickness so I start taking it before my flight and daily throughout the cruise. Despite rough seas on the Pacific, Atlantic, and Tasman Sea, the only time I've gotten seasick was in the Panama Canal! That was due to watching the shoreline go by, not due to rough water.