I live in MO and have adopted. There are several types. You can foster/adopt from Missouri Division of Family Services, and this is for free. You don't pay anything. You would have to foster the child for 6 months and then can adopt.
A private adoption is one that is set up between you and a birthmother. It is usually arranged by an attorney or an adoption agency. These can rage in price from $10K up to $40K depending on what the B-Mom asks for in help with housing, etc. There are many agencies that assist in this type of work.
We started with MO DFS, got nowhere (however, others have done well with this route), went overseas and waited for two years with no results. I finally found a woman in Colorado Springs, CO who puts together adoptive parents and birthmother/babies. I hired her in Jan, 2007 (her fee was $2K) and got a call in April, 2007 that there was a baby born (on the ground) in OK City and if we wanted her we had to get on the road immediately. We went and I now have a beautiful 4 year old. We worked with a private adoption attorney in OK to handle the legal work. The attorney's fee was $23K
The bottom line is if you want to adopt, you will find a way to finance it. Whether it be free through DFS, or to pay a private attorney/agency. A lot of folks take out home equity loans, have fundraisers, sell things on eBay...where there's a will, there's a way. Also remember, there are tax incentives available. You can also get a tax credit through your husband's FLEX/Cafeteria plan, and yes, take advantage of the adoption subsidy your husband's company offers.
I am a huge proponent of adoption. In the adoption community, we say that your baby will find you. Mine certainly found me. Good luck!