I can't stop using crack. What should I do?

I am a crack addict I guess because I can't stop using. I thought that because I only binged on weekends I had it under control but after enough Monday mornings feeling like death and promising myself and my girlfriend who also indulges that I'd never do it again I made a serious try at actually not smoking this last weekend and by Friday midnight I was calling my dealer every five minutes demanding a meet up and then it was at home all weekend with the curtains drawn, as usual.

I can't afford rehab and I can't stop so what do I do? Should I try to cut down by buying less or by limiting my access to money on weekends in advance? Does this ever work?