Here are some instructions for making butter the old fashioned way as well as more modern methods. Here are very good instructions with pictures for making butter with an electric mixer. They also have info on the health benefits of butter. Here is a pictorial instructions on butter making starting at the cow.
If you want to stretch your butter (you can do this with homemade or store bought butter) and make a soft spread that can be stored in the fridge you can do something that my mother-in-law taught me. If you take 1/2 butter and 1/2 oil and blend them in your blender or with your mixer you can make a very nice spread that tastes good and works well. We enjoyed our fresh
butter on fresh homemade whole wheat bread. Very yummy! This butter was not only cheap but very healthy too and a great learning experience.