We used an unlicensed facility we found on Craigslist for daycare for our two oldest when they were little. It was still freakin' expensive. I don't remember what we paid because I was a student and got a subsidy, but would have been $400 per week, per kid for full freight in 2005. By the time number 2 came along in 2007 there was no point to Mr. Marvie working. We now have the 4 year old in a part-time preschool program. We are not currently in the US, but we pay $530 per month for that in our extremely wealthy neighborhood here.
The difference in quality between the littlest's preschool program and the in-home daycares the two biggest went to is absolutely stark. Both of my elder boys went to Kindergarten not understanding basic classroom social skills -- talking, listening, sitting for circle time, etc. -- and were delayed in their use of language even though they were way ahead with reading and writing. The littlest uses SO much more language than they do (and okay, some of that is the local language but how awesome is that, that he communicates bilingually with kids from all over the world, at four?) and has the basic skills he needs for Kindergarten down. He's also happier, does art projects, sings songs, goes on field trips and has a much more structured day, which all three of them needed. It's hard with a home daycare for there to be structure and learning, because there's only one person to manage everything -- cleaning, cooking, minding the kids, teaching, etc. His preschool has a lower ratio than the home daycare, and someone else manages the infrastructure, which I think drives the quality.
It's totally a case of 'when you know better, you do better', and in-home daycare from Craisglist was what we could afford when the biggest were young. But if I had the option, I would never, ever do that... this is one place where quality is huge.