What do you girls think??

So my brother and his wife are not capable of having children because his wife doesn't have a functioning uterus. They want a little one and they were thinking of getting a surrogate me being me and loving both of them very much offered to be theirs. I told them that I wouldn't ask for a crazy amount of money or anything just to help me get my drivers license and help me get a cheap car. I wouldn't even ask for that but they won't allow it to happen that way. I just want them to be able to have a little one. I told them when I have had the proper time to heal after my last baby ( currently 21 weeks along with) that I will be more than willing. I just want their baby to have the maximum chance of being the healthiest that it can be.