Teeth whitening

I don't smoke, but when I was younger, I didn't like coffee, so my teeth were quite white. As I got older, I started to like coffee and drink a lot of it, so my teeth gradually darkened. Even when I use whitening toothpaste, I don't notice any effect, and whitening treatments at the dentist are too expensive.ㅠㅠ How do you all manage your teeth care?