How do I adopt an infant/toddler through foster care??

I'm so confused. Someone said I would need to go through an adoption agency but those cost alot of money. I thought you could adopt through foster care for very little to none??? OBVIOUSLY, it's not about free adoption..... I was in foster care. It's super important to me. Don't know why that was even said ๐Ÿ˜‘๐Ÿ™„ My husband and I have been trying for our first for over 3 years and always have talked about adoption as well.... Was just trying to see how to go about the process... and I understand that you have to foster to adopt and that you're not just given a kid...... I was asking about the adoption part....... Nothing is guaranteed in life ever.... Need helpful information from people, who have gone through the process please