It is your fault if you allow the recruiting process to get to the third interview without at least knowing if the salary range is acceptable.

If you lack confidence in talking money, here is what you say:

"I'm looking for $120K to $130K. Before we get further into the process I want to confirm that this salary range is what would be discussed if we get to an offer."

You might add:

"$120K is my minimum but I am really hoping to find a role at the higher end - $130K is what I'm aiming for, depending on the job."

If, after saying all this, you get lowballed, then you have good reason to be very annoyed, and express calmly but clearly that you have had your minimum salary on the table since the first phone call." At that point you withdraw from the process and go look for a job with a professional company.