Very good Indian food, especially for the price. $5 can get you a small serving and a freshly grilled piece of naan - plenty for one meal. For a dollar extra you can get a large and have some leftovers.
My favorite has always been the mango chicken curry made by Rita (the cart closest to fifth ave). You can choose your spiciness on a scale of 1-10. Definitely the best quick meal for $5 in Oakland.