how to get my dog fixed for free in buena park ca(orange county)?

i have a pitbull terrier 4months ..i rescued her on the side of the road when she was a puppy she wa sleft neglected. i have a regular paying minimum wage job and i have to pay for school and car insurance so i cant afford to pay for her to get fixed. is there any way i can get her fixed for free ? and get low costs shots ? i got her first sets of shots already but i had to borrow money from friends and family. can somebody help please , i dont wan tto get rid of her everyone in my family including me is attached!