There are no online sites that allow viewing of actual birth certificates for free or for a charge. However, you can access public birth records for free through state government sites, and sites such as Ancestry.com and Familysearch.com offer access to multiple family records dating back as early as the 1600s. Genealogy sites typically allow a limited free search followed by a member fee in order to access more detailed information.
Searching vital records is the best way to access birth information for free. Census records for the state in which the individual was born provide approximate birth information, and from there, you can contact the local jurisdiction in order to access more detailed information. While genealogy sites charge a fee for members, they are a great option if you are seeking information in order to create a family tree or family history report.
If you are looking to access your own birth certificate, it is best to contact the public health department in your county of birth. There are multiple online sites that offer quick access to legal birth certificates, but they charge a fee, and it is important to verify that these companies are certified and licensed in order to ensure you receive a valid copy.