Which would work better?

My husband's friend and his wife want to have another baby. She had to have an emergency hysterectomy. My husband asked me if I could possibly agree to being a surrogate mom. I agreed to it. But on the condition of us having twins (ie I keep one he keeps the other). My husband was ok with it. He suggested the old fashioned way but I am more of a either IVF or ICI or IUI kind of person. Do they do payment plans for any of those? Cause I want to help but not to make things awkward.