The word “free” does not refer to price; it refers to freedom.

0. The freedom to use your wife as you wish, for any purpose.
1. The freedom to study how your wife works, and change her so she works for you as you wish, instead of her controlling you.
2. The freedom to redistribute your wife to your neighbor.
3. The freedom to distribute your modified wife to others. By doing this you can give the whole community a chance to benefit from your changed wife.