If you do not want to use straight vinegar as a fabric softener, my wife has come up with a hybrid recipe that works:

6 cups warm water

3 cups white vinegar

2 cups hair conditioner (Suave or Dollar Tree brand is fine)

1 cup baking soda (Optional)

Mix 2 cups warm water and baking soda until until dissolved. Slowly add the vinegar as it will bubble up since it reacts with the baking soda. The baking soda is a freshener, but you will lose some of the softening due to the acid neutralization.  Add the hair conditioner and rest of the water. Mix well. Shake before each use.

Yields 96 ounces. Use 4 ounces per large load. Do the math. It's cheap.