How does financial services (charity/discount) work at hospitals? How much can I be discounted?

I'm about to apply for financial aid at a hospital making $11/hr @ 30hrs/week and was wondering anybody's experience with these services. I know it's on an individual basis, but I was wondering the success of some individuals that have tried it before. Currently, I'm a temp and make $11/hr and less than 40 hours per week. I pay $700/month rent including utilities; $50/hr on groceries; $75/month on cellphone because I have no landline; and also have collection agencies after me because I defaulted on credit cards. I really can't pay a bill of $2800. To top it off, I told the paramedics I had no way of paying this and they told me the city would. I went in because I couldn't stop regurgitating and felt I was going to puke my liver out. So I have charges of CT scan and various lab tests. I would of been happy with the IV treatment of nausea. Now I just want to know the success these hospital services can offer me. I'm 24 uninsured and already in debt and I don't need medical bills over me