I think costs vary. When I did DBT, the group cost $65 per session (1 1/2 hours) and my therapist charged what was normal for the region ($120/session). Both were billable to my insurance.

I've been trying to get my son into a DBT group and the costs range from $95 - $150 / session (not billable to insurance) plus a therapist (billable to insurance). The two groups I've identified are "by-the-book" DBT groups, not "modified"...plus parents attend.

As an aside - DBT groups don't typically offer a therapist on call. If you have a DBT-trained therapist, which some groups require, that therapist will provide coaching calls. These can be 24/7 or during a set time (mine offered them between 9 am and 8 pm). Coaching calls are not crisis calls or therapy-by-phone - they are designed to offer coaching in using skills, so you are supposed to be able to describe which skills you've tried before you call. Also, typically, if the call goes over a certain amount of time (typically 10 minutes or so), you will be billed for that time. If you have a DBT-trained therapist who is following the protocol, this will all be explained ahead of time and you should have a contract that describes it all.