These are the prices Candi emailed me (sorry I forgot to put them up earlier) for the Mark Twain Riverboat Cruise:

One Hour Sightseeing: departing at 11:00 am, 1:30 pm daily, and 4:00 pm daily
Adults $14.00 + tax
Children (ages 5-12) $11.00 + tax

Two Hour Dinner Cruise: departing at 6:30 pm every evening
Adults $36.95 + tax
Children (ages 5-12) $21.95 + tax

Reservations are only required for the dinner cruise. Boarding begins 30 minutes prior to the above departure times. This our schedule from Saturday of Memorial Day weekend until Labor Day Weekend.