In Kentucky where I live, even a person on welfare can adopt. It's even answered in one of their FAQ. The way they get around it is that they say that your entire income can't be from welfare. So, basically you could adopt/foster 8-10 kyds if you had the room, and operate a small daycare for outsiders in your home and qualify, or one spouse could have a part time minimum wage job at the time of qualification. It's also a myth that each child of a different sex has to have it's own room, or two to a room, etc......While they have age limits on different genders sharing rooms, for all intents and purposes you could have "adequate" beds which could be 3 bunks to a room, for instance. I don't know how it is in other areas, but if someone leased a huge farmhouse and cleaned it up, set up a barracks of sorts, and showed some income somehow, they could make a killing off of being foster/adoptive parents.
They don't post amounts on their state website, it's always "on a case by case" basis, but I know of one famblee (poor, uneducated, hillbillies) who go to my MIL church who have a revolving door of foster kyds and a few "special needs" ones they have adopted who are teen aged, and they bring in over 5k a month in cash outlays alone, and then they get food and medical. They have little overhead and NO overhead which the state doesn't outright pay for or subsidize, and it's a known fact that in just a few short years they will "retire" (after having never really worked) and they are only in their late 30's. These people and many like them actually make a career out of foster care and the occasional adoption (generally of a terminally ill or severly disabled kid and they get extra for that) and they basically are getting paid to run a 24/7 day/nightcare facility.
So, at least in this state, even someone on welfare can adopt, singles can adopt, and the childed can adopt from the STATE agency. However, when it comes to PRIVATE adoption, ie;Healthy, NON African American, newborns, then it's true that you have to have VERY deep pockets. First you have to show complete self sufficiency and be above middle class income level, AND you have to pay the moos "expenses". Depending on the agency, these "expenses" could be college tuition, living expenses for a year or longer after adoption, and outright cash outlays to the moo.