Recently began making my own laundry soap, ds has environmental allergies and so far it seems to be cleaning as well as All Free and Clear.
You will need:
Bar Soap (Any kind, I have used Felsnaptha and Ivory)
Borax
Washing Soda
Water, Large container, Funnel is helpful
Grate 1/3 bar of soap, melt in 3 pints of water in large pot. When soap flakes are melted add 1/2 cup each borax and washing soda, continue to stir on low heat until thickened. Add to large container with 2 gallons of hot water.
This stuff got real thick on me, I think I may break out a large covered bin that I can just scoop it out of. I only had small laundry jugs though so I couldn't add as much water.
On the bright side our laundry is faintly scented by the Ivory, it's been 3 years since I've had a nice scent to my laundry.
My cousin does this and they like Irish Spring, you can use any soap you're not allergic to.