Where can I search for birth records? I am looking for a Great Grand father and my Grandmother's mom.?

Ok well Willie R. Poston DOB is 1914 DOD 08/02/1995 his dads name is William D. Poston. DOB 1885 DOD 07/05/1958. Both are burried at Guilford Memorial Park in Greensboro, NC. His wife is Alberta Hudson Poston, DOB 09/14/1914 DOD 06/28/1998. No date on marriage date. Willie R. Postons Dad William D Poston and mother Lona Reynolds Poston DOB 1892 DOD 1980 was both born in Georgia. Willie has a sister named Myrtle Poston Beck. The 1930 Census says Willie, at the time was 16, Myrtle at the time was 13, was both boarders of the home not Children and it also states their last name was REYNOLDS. My Grandmother's names is Lillie Gaynelle Poston Watkins. Her DOB is 01/20/1936 DOD 05/30/1988. She is buried at Lakeview Memorial Park Greensboro, NC. She comes up in everything as Gaynelle. I do not know her birth mothers name or where she is from. Is there a way to search information online free? I have paid several sites and am still stuck with the same information.