Keith,
You can just keep the snake. Eastern Indigos are legal in TX. The only federal permit you would require is to transport the snake out of TX. If you don't want to take my word for it. Here is the Federal Fish and Wildlife contact in charge of Eastern Indigo permits. Hope this helps.
Victoria Davis, 404-679-4176
Take care
Joe Deavers
J & S Reptiles
www.jandsreptiles.net