Second job interview, they still won't tell me how much the pay is

First interview was more of a chat about my experience, etc. I asked about pay, guy said he didn't know and asked me my salary expectation. He told me it was within budget. Second interview, I asked again. Guy talked about some bonus, but again no specific answer. Said that it would be adressed in third interview. Isn't salary one of the first things that should be clear from the start? Why do they think people look for jobs? Obviously vocation is a big part for professional jobs, but come on. If I'm going to consider a job offer I need to know how much I'm going to get paid before giving my time up to a long interview process just for them to mayyybe tell me at the end what my salary will be...