How to know what is it that I am getting charged for.

US East (N. Virginia) USD 6.80

68 GB-Mo USD 6.80

This looks like 68GB of gp2 storage in us-east-1, getting charged at 10c per GB-month https://aws.amazon.com/ebs/pricing/

You should be able to see this in the EC2 -> EBS -> Volumes section of AWS Console in the us-east-1 region https://us-east-1.console.aws.amazon.com/ec2/home?region=us-east-1#Volumes:

Check the Volume state column for each volume to see if something is left hanging around after you thought you had deleted it.

To expand on what 68GB/month actually is - basically this means you provisioned 68GB on the 1st of the month (or it was pre-existing from the previous month) and it was present for the whole month.

If your account is in-scope of Free Tier then you get 30GB/month for free, anything above that would be chargeable, so in this example 38GB would be chargeable. If your account has exited Free Tier then the whole lot is chargeable.

You can check your current Free Tier entitlement at https://console.aws.amazon.com/billing/home#/freetier

There are a lot of useful links here with advice on how to avoid unwanted charges https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/checklistforunwantedcharges.html

You mention you are using this for school, have you considered AWS Educate? https://aws.amazon.com/education/awseducate/

Sounds like it is free, so you wouldn't get any unexpected charges like this https://aws.amazon.com/blogs/training-and-certification/aws-educate-expands-access-to-free-cloud-education/

https://www.awseducate.com/registration/s/learner-faqs

Are all your courses free? Is there a paid component?

All our courses are absolutely free, including access to labs, badges, job board and various other features of our platform.

Likely you have some EBS volume that may not be attached to EC2 instance but hasn't been deleted in us-east-1 region.

Hello,

As a general guideline, you can look at the pricing of each service within the documentation. To estimate the price, you can use the pricing calculator online.

However, in your case, you have some provisioned EBS storage (PIOPS) that incurs charges. To delete the EBS volumes, go to the EC2 Console > Volumes > Volume 1234 and then delete that volume.