I use white vinegar as a fabric softener but not in every wash.
Here is the recipe from the Debt Free, Cashed Up and Laughing Book.
2 cups of grated soap – I use the 4 pack of homebrand laundry soap and grate it
1 cup washing soda – this is found in the laundry aisle of the supermarket, usually up the top
1 cup borax – this is found in the cleaning aisle
1 pkt (500g) of bi-carb soda
Mix all together and use 1 Tablespoon for top-loading machines and 1 teaspoon for front loaders.
Here is another recipe:
1 cake of laundry soap
1 cup of letric washing soda
1/2 cup of borax
Grate the soap and mix all the ingredients together. You only need 3 teaspoons per load for a top loader and 2 teaspoons for a front loader.