How can I get low cost for sonogram?

I didn't make enought money from my work, and now I have a problem with bleeding between period. I went to health department at Gwinnett County and I had my pap smear done about 3 months ago, the result came out normal. however, the nurse told me that I need to see the OBGYN. The doctor at OBGYN told me that I need sonogram base on my symptom and it costs $300 and I try to figure it out how can I pay for. I live in Georgia. Is some body knows where I can get low cost for sonogram. I went to health department and they didn't provide the sonogram test. Thanks guys.