There are onboard charges for all Thomson cruise ships, including the Thomson Destiny. These charges include any shore excursions you may want to participate in, various entertainment activities aboard the ship, spa and hair salon services, any type of laundry service, and there are additional charges if you wish to have a safety deposit box. The specialty and a la carte restaurants on the ships on the also charge a cover price. Typically these cover prices are between 12 and 15 euros. Also, any purchases you make in any of the onboard shops would not be included in the price of the cruise.
For more info, see Thomson Destiny Cruise Ship