Some therapists will offer a cash discount. Also make sure you find a therapist who is very familiar with personality disorders and who isn't afraid to get down in the trenches with you as far as DBT/CBT work. If finances are an issue, then it's important to be politely assertive and stress upfront that you don't have much spare money and so your sessions need to count, you need a proactive therapist who will do more than just sit there giving you placating nods and comments.

Also, a lot of therapists will prefer not to label you, even if you meet the criteria for BPD. I ran into that while trying therapy, I never received a diagnosis, but we did the work, anyway. I think the reason is because BPD gets a lot of negative stigma even among psych professionals (which is ridiculous, but true none the less), and also because they don't want a person with lots of shame issues and a weak sense of self latching onto a label like BPD as if to say, "This is what I am, I am bad, and this is what it's called." They would rather have you focusing on specific issues and seeing yourself as a unique and complex human being who has some issues, not as "a borderline" and whatnot.