First of all, hear me out. If you don't make laundry detergent already, I am here to convince you that it is so ridiculously, stupidly easy, even I can do it. You don't need to invest more than 10 minutes, and even that's probably an exaggeration. The cost savings compared to the time investment is probably one of the absolute highest ratios I have seen, so yes it's worth 10 minutes!
I don't remember where I got this recipe from, but if you were to search for homemade laundry detergent, you would get approximately 1 bajillion hits, so I don't feel bad sharing it.
Very roughly 4 gallons water
1 bar of soap, grated
1/2 cup washing soda
1/2 cup borax
So here are my pointers. To procure these items, I would first suggest you check out alice.com for the washing soda, cause that's going to be your toughest find (and it's not that tough, is it?). It's currently priced at 2.99/box. While you're at alice, if you don't already having some Borax, you can pick that up there too, 4.29/box. I haven't the faintest how that compares to what you'd pay at Walmart, but it might be a bit cheaper there. You will buy these two items once and have soap for at least 3 years I would guess, so I don't sweat it too much. For the bar of soap, I like to pick up Ivory when it's on sale, I know Fels Naptha is like the gold standard for this process, but I've never seen it locally, and I'm not willing to pay what Amazon wants just to give it a try. Ivory works just fine. It's nice to have a 5 gallon bucket to make the soap in, and store it, but something of a comparable size would be fine too.
So for the actual production part of things;
1. Fill your bucket with water. I try to do this the night before, so I can use cold water and it will come up to room temp.
2. Dump the soap and a couple of cups of water in a saucepan, and heat over medium until the soap has dissolved.
3. Remove from heat, add 1/2 cup each of Borax and washing soda. Stir to combine.
4. Add to bucket of water.
5. Let it sit overnight. In theory, this will solidify to some point, and become gelatinous. This has NEVER happened with my concoctions, but it still works just fine.
6. Use 1/2 cup per load of laundry.
I wish I had some specifics for cost comparison, but what I remember from when I actually figured it out is that this costs less than one cent per load. I do remember that I couldn't get commercial soap for less than 11 cents per load, even with coupons and sales. A batch of this lasts me roughly 4 months, and I do laundry every day.
One thing to get used to is that your pants no longer smell like a mountain forest. I'm okay with that, but it is an adjustment. My absolute only concern is that my bath towels have gotten a bit musty smelling lately. Because of this, I no longer leave a load in the wash for any length of time, it really has to be dried pretty quickly. I washed all the musty towels in hot water, with commercial detergent, and machine dried them on hot, and that worked just fine. If I have to do that every few months, I'm okay with that!