it really varies!! like which country, agency, age of child, even gender! and special needs or healthy? independant or agency? only a couple countries let you go "indy."
i would say 30K is average. Russia is usually more like 40K these days
but, lots of women on this board are spending that much money on high-tech cycles, and some are getting their girls but some are not, either because they don't get pg or have an opposite or have a m/c
so even though adoption is FAR from a "for sure" thing, i feel it's better odds for me than high-tech! plus, i don't feel like i'd be 1 of the "lucky ones" if i tried high-tech! and my heart is with adoption so... money is relative. a lot of people spend that much on a new SUV or car, but can't justify spending it on a child.
but also the gov. will give you back 11K in tax credit and there's all sorts of adoption loans & grant programs!