You get a main entree like a burger or pizza and sometimes they come with a side like in a combo meal (fries, green beans, etc. depending where you go), a dessert and a drink. I'm pretty sure you can order a large drink too.
Cosmic Rays at MK is a great choice because you can get a half chicken/rib meal that comes with mashed potatoes and green beans and you also get a dessert and drink. It's great value for the DP.
Not too sure about pizzafari since I like tusker house and flame tree better, but I think you'll get a pizza, (maybe a side salad) and dessert and drink.