The advantage of going through a rescue sanctuary is that you can visit and learn the personality of your bird before you take it home.
It is better to get one that has already gone through puberty.
All of mine are rescues from Craigslist. Some I paid the rehome on them without even seeing them first. I paid $100 for 2 Cockatiels that I bought in a parking lot. They came to me in two little cardboard boxes and I did not see them until I got them home.
I do not require anything from my Cockatiels except that they are happy. I am one of the few that will rescue sight unseen. Of course I do not recommend this kind of rescue for others.
www.rescueme.org covers all states and most are on there from their humans who can give you info on them.