They NEED to talk about this together. The woman trying to conceive, will have to call her insurance. (I'm sorry to tell you, most insurance companies here don't deal with surrogacy.) What would be the smart thing, if for the surrogate to sign up with a REPUTABLE agency. The mother could hire her through that agency. The agency will figure out insurance, payments, etc. usually the mother has to pay cash, because it would be a rare occurrence for insurance to cover the medical needs of a surrogate. (Actually, times might have changed. I worked in insurance 4 years ago. It's possible they cover now.)
Here is the thing about surrogacy. In our country, there are almost no laws on the books. Contracts are not usually binding. (Read about the surrogacy controversy in the news. The family wanted an abortion and the surrogate didn't. Even though the abortion was in the contract, the contract was not legally binding.) Neither party is really protected under the law. I would make sure your friend knows what she won't do. How many rounds will she be willing to go through? Is she willing to carry twins, triplets? Doctors always try for a single, but fertility often leads to multiples. Is she going to be a gestational carrier, or will her DNA be involved? If so, how does she feel about a child being half genetically hers? What is she going to allow the mother to demand? Natural birth? C-section? Abortion, if there are abnormalities? What if there is something wrong with the baby, and the mother no longer wants the baby? What will the surrogate do? If she has a difficult pregnancy and has to leave work, how will she survive. If she has a family of her own and can't function, how will they deal with it?
If you friend is doing this for money, she should not do it. I'm not saying she is, I'm just saying IF. People don't come away with very much money from surrogacy. Not when you factor in conceiving, carrying a child, all the appointments, time missed from work and family, etc. Surrogacy should be done to give life.
Personally, there are grey areas law wise. I could never be a surrogate, because of the lack of binding contracts and no laws. She should take the lack of legal protection for both parties, into consideration.