I'm going to post a recipe I have for laundry soap. It does call for the Fels Naptha, but according to some research I've done, you can use any brand of bar soap. Not sure if the results will be the same for ring around the collar or the likes, but I'm sure it's worth a try in the abscence of the fels naptha product. Also, I've just checked the pkg for the company who makes it, which happens to be “The Dial Corp” in, well the address listed is Scottsdale, AZ 85254. You may be able to contact the company and see about buying in bulk, which may also me cheaper then buying in the conventional store.
So here's the recipe:
1 bar of soap (whateverkind you like)
1 box of washing soda (I have the arm & hammer brand)
1 box of borax (this is not necessary, but found it really kicks the cleaning up a notch)
A 5-gal bucket w/lid
3 gal. tap water
Long enough spoon to stir
Step 1: Put about 4 c. water into pan to boil. While waiting for the boil, start shaving the bar of soap into water. Stir the shavings until dissolved.
Step 2: Put three gal. of hot water into the 5 gal. bucket. Add soapy mixture from stove. Add 1 c. washing soda, stirring for approx. 2 min., then add 1/2 c. borax if desired. Stir for another couple of min. Cover and let sit. After 24 hrs, should resemble a gelatinous slime, paler then the shade of soap you used. Use 1 c. per load, getting approx. 48 loads of laundry from this one mixture.
I've gotten about 2 to 3 mixtures from a box of borax and washing soda ea. plus the one bar of soap per mixture. Which for me, translates to about $8 for 3 buckets of mixture, and last me about 6 months total.
Hope this helps a little.