Modified DBT groups aren't expensive. I found one in my area for $30 a week.

Real DBT groups are expensive because you have group plus an individual T on call 24/7. No real DBT groups in my area accepts insurance. Well one at the hospital accepts Medicare, but I don't know if it's real or modified.

Do you have a county mental health clinic? Mine offers free groups if you're a patient there.

Have you tried searching psychologytoday.com?