Can some one confirm why RDS free tier is charged a small amount?

I am trying an RDS free tier and noticed that it still charging a small amount per day. Can someone confirm that it might be due to I have selected any paid service in the features or does it still apply to the free tier.? Below is the line showing the charging part in billing. If there is anything that can make it 0 let me know. $0.12 per GB-month of provisioned GP3 storage running MySQL 2.935 GB-Mo