Something that I've been doing for a while now to save money is making my own laundry soap. This really is such a great way to effectively clean clothes very cheaply. It is so easy to throw together and simple to use. All it is is this:
1 part Fels Naptha laundry bar soap
2 parts Borax
2 parts washing soda
What I do is grate one whole bar of Fels Naptha~ it comes out to be about 2 cups~ into a plastic container and add 4 cups each Borax and washing soda and mix it up. (I've also been adding powdered Clorox 2 to the mix just because I have it but that's completely optional. You could also add a few drops of essential oil for scent if you like. )
To do one large load of laundry, I sprinkle in a few tablespoons. That's really all it takes! In fact, I keep a metal 1/3 C. measuring spoon in the container and fill the cup about about half full to wash 1 large load.
I found this "recipe" in one of the cloth diaper forums, back while I was pregnant with Josh, in a thread about saving money. And save money it does! All the ingredients together cost about $9 for 3 batches, and considering I get about 60 wash loads per batch, that comes out to about $0.05 per load.