I love the Jiffy brand muffin mixes! They cost between 33¢-50¢ a box . They come in 6 flavors: apple cinnamon, Corn, blueberry, raspberry, oatmeal, bran with dates,and banana nut. Usually they call for 1/3 c. milk (I use reconstituted powdered milk) and 1 egg- you stir and bake. One box make 6 good sized muffins! Jiffy also make other products like cake mixes, frosting mixes and other stuff! Take a look at their web page for recipes, and to see the complete line of products!
See Biblical Womenhood for more frugal tips!