I don't know about other states,but AZ has an "Access" program.Its insurance threw the Department of Economic Security,they also deal with foodstamps/ebt.Alot of people aren't eligable here anymore (they really cut benefits the last couple years) but if your state has a program like that I would suggest applying.They may be able to help you wiht insurance,or at least an emergancy type insurance that can help/completly pay for detox..Possibly rehab.
I went to a 7 day detox in 2005,and the access thing covered it.But it wouldn't cover the costs for rehab :/
Definatly check out any local/state help you can get.If nothing else,its worth a shot.Good luck to you!