To make your own laundry detergent you get the old fashioned kind of laundry soap - it's usually yellow - I think it might be called sunlight soap. You get it in the same aisle of the supermarket that you get all the other laundry things. You must then grate one cake of it & put it into an old 2 litre detergent bottle & fill with warm water. If you put the cap on and leave it overnight then shake it you will end up with laundry liquid.

I found it worked as well as the commercial ones & it was far cheaper. The grating is a bit of a pain though. I was avoiding chemicals as I was having problems with asthma and rashes at the time. Luckily I don't have either anymore so I don't go to those extremes anymore.