You check with your state wildlife first, some states have bans on them.
Then you contact Federal wildlife to obtain a permit only if you are buying one out of state. That's pretty much it
Here is a web address for a breeder and on the site he has the info and who to contact. I dont think the permit is to costly, but the Indigos are a little pricey 600.00-1500.00
www.easternindigo.com
I think they are awesome but get rather large and need a way big cage lots of floor space and climbing.
They say they are so sweet that some will actually curl up and sit on your lap like a puppywhile you watch TV.
I think it was Ironhead who had them as a child and his would sometimes sleep in the bed with them
I have loved them ever since I was about 10yo soon as I get a place with some more space I will have one that's for sure.