Under NO circumstances would I ever recommend that a person cut corners on their adoption costs by failing to obtain experienced-in-adoption legal expertise. Every aspect of the adoption needs to be done absolutely correct and you do not want to leave any legal loopholes open in case in the future, biomom. biodad or both should change their mind and seek a way to rescind the adoption (look through the archives to see what I mean). The emotional security and stability of my child's life is worth every penney in legal fees. NOTHING is more important than that. I don't care HOW agreeable the parties seem today, situations change and sometimes bioparents decide that because THEY have finally gotten their act together, they want to overturn the adoption and get "their" child back. Don't be penney wise and pound foolish. It will be one of the best investments in your child's future you can make.
FYI- I have been on several web support lists for adoptive parents for over 5 years, and I have heard some stories that will make your hair curl about overturned adoptions. Take no chances.