I made my own laundry soap for about 8 years. I'm not making it now only because we've moved to Germany for one year. I usually make enough powdered detergent for one year, 2 adults and 1 messy kid. 3 bars of fels naphtha or zote soap, 1 large tub oxi bleach (like Oxi-clean but I bought generic), and 2 boxes of washing soda. You can the scent crystals, a couple of brands make them, if you want scent. I've used this to wash cloth diapers (w/out scent), everyday clothes, greasy work clothes, muddy toddler clothes, etc. It seems to work pretty well and doesn't lose potency like the DIY liquid detergent, which is what I first made.
If you use a food processor it's easy to grate the soap really fine. Also, some stores carry Zote soap flakes (just compare the weight to the bars), which doesn't require grating at all. Our old Walmart did anyway.