"Career change" dogs from GDA is I believe $1000 but there is a long waiting list for them. It is at least 3 years from what I have been told.
The adoption fee is $1000, plus the additional cost of training the dog to be an anxiety service dog (which GDA doesn't do - you'd have to find and pay an independent trainer) - unless you meant that you want a comfort/companion animal, not a service dog as defined by the ADA (one trained to do a task to assist someone with a disability). As Doug mentioned, the waitlist can be long, though if you're willing to take to take a dog with minor medical issues (allergies, heart murmur), the wait can be shorter. Alternatively, you could volunteer to raise a puppy (which has been a great experience for my child who has anxiety) and if the puppy is career-changed, the adoption fee is waived for the puppy-raiser.
Thanks! Your answer is awaiting moderation.