I think Tomsteve sums it up.
As far as the cost, they vary like crazy. I went to a dual diagnosis facility I don't even want to say what it cost. Thankfully I have insurance. I'm not sure what the IOP program I attended for a couple of weeks cost....I did find, however, that since I was feeling pretty stable at that point my time was better spent in AA, than in an IOP. That was just me.
I do know that places will negotiate big time. I think they like not using insurance but they will ask for a payment upfront. My experience was half the total cost.