How to disable AWS Cloudwatch metrics

I'm new and am trying to work with AWS. I develop small lambda functions and have created some dynamodb tables. I don't expect there to be any costs, because I should be in the free-tier, but since last month I am seeing costs for "Cloud Watch Alarms". Not high costs, but I got billed $0.53. Why I am getting this bill even though I am using AWS free tier.

Billing info:

$0.00 per alarm-month - first 10 alarms 10 Alarms $0.00
$0.10 per alarm-month 4.277 Alarms 0.43$

I don't want these cloudwatch metrics right now. I only want to store log files. How can I to disable these cloudwatch metrics.

Thanks,

You have configured, maybe unintentionally, a Cloud Watch Alarm.

Fortunately it's quite easy to remove it.

Go to your AWS Dashboard and select Cloud Watch:

On the left-hand side, click on Alarms. Select the Alarm which you want to remove and delete it.