Yes, you need a voucher, but you purchase them right at the restaurant. It isn't the kind of voucher some people talk about on the boards that you send away for ahead of time.
When we went, it was $11.99 + tax for your drink, your entree, and then a drink and either a popcorn or ice cream bar later. We got the Tusker House chicken deal which came with a LOT of chicken, mashed potatoes and veggies & the salmon platter which was salmon, rice and veggies. Both were very good. You can go to Pizzafari, Tusker House or Flame Tree to get the meal deal vouchers.