How do I go about finding my birth parents without my adoptive parents finding out? I also don't have a lot of money so free is better.

1. contact the adoption agency and ask to leave a letter with your contact information in it in case your birthparents are looking
2. Do the same at the courthouse in the county you were born/adopted in.
3. Register on reunion websites, such as ISSR, adoption.org and adoption.com
4. If you have information such as her name and birth date, you can look into hiring a private detective to search.

Why don't you want your adoptive parents to know?