I just wanted to add, I follow the same recipe with one exception and it is a great recipe. It works great and is very cheap to make. Like nvmommy said it does go a long way, considering how little it's costs to make. But around my area, you can not find fels naptha soap to save your life, so I substituted zote soap (which was recommended and found easily around here) and it works perfectly. So if anyone has any problems locating the fels naptha but the stores in your area carry Zote laundry bar soap (found on the laundry detergent aisle), use that. Or you could just always order fels naptha online, but I am an instant gratification kind of person and wanted my soap right then.
One suggestion. Keep any and all old and empty detergent bottles, milk jugs, whatever. You will need them.