You might try Legal Services, however, you need to be very low income to qualify for their services. The court will appoint someone if you are in fact indigent. You should not go without representation.
You need to have an attorney, do not do this by yourself. If you are indigent or very, very low income the court will appoint one for you. Since this is your first offense, an attorney may be able to get this dismissed. Your credit rating is not really relevant other than perhaps proving you have no assets on which to draw.
A passenger cannot be charged with DUI for the simple reason thta he wasn't driving. Were you charged with something else like public intoxication? You definitely need to get an attorney to straighten this one out for you. Good luck.
Actually the suggestion to go to either a shelter or to the court and actually view these cases are both good ones. Doing actualy research is the best way to understand and to subsequently write about these situations.