If you’re running in an account that was created for you as part of an AWS event, there’s no need to go through the cleanup stage - the account will be closed automatically.
If you’re running in your own account, make sure you run through these steps to make sure you don’t encounter unwanted costs.

Removing the CloudFormation stack used for FIS

aws cloudformation delete-stack --stack-name $FIS_EXP_NAME

Cleaning up HPA, CA, and the Microservice

cd ~/environment
kubectl delete hpa monte-carlo-pi-service
kubectl delete -f monte-carlo-pi-service.yaml
kubectl delete -f inflate-arm64.yaml
kubectl delete -f inflate-amd64.yaml
kubectl delete -f inflate-team1.yaml
kubectl delete -f inflate-spot.yaml
kubectl delete -f inflate.yaml
helm uninstall karpenter -n karpenter
kubectl delete -k $HOME/environment/kube-ops-view
kubectl delete -f

Removing the cluster, Managed node groups and Karpenter pre-requisites

aws cloudformation delete-stack --stack-name eksctl-eksworkshop-eksctl-addon-iamserviceaccount-karpenter-karpenter
aws cloudformation wait stack-delete-complete --stack-name eksctl-eksworkshop-eksctl-addon-iamserviceaccount-karpenter-karpenter

aws cloudformation delete-stack --stack-name Karpenter-eksworkshop-eksctl
aws cloudformation wait stack-delete-complete --stack-name Karpenter-eksworkshop-eksctl

aws cloudformation delete-stack --stack-name eksctl-eksworkshop-eksctl-nodegroup-mng-od-m5large
aws cloudformation wait stack-delete-complete --stack-name eksctl-eksworkshop-eksctl-nodegroup-mng-od-m5large

aws cloudformation delete-stack --stack-name eksctl-eksworkshop-eksctl-cluster
aws cloudformation wait stack-delete-complete --stack-name eksctl-eksworkshop-eksctl-cluster

aws cloudformation delete-stack --stack-name karpenter-workshop
aws cloudformation wait stack-delete-complete --stack-name karpenter-workshop

If you get any error while running this command, perhaps it might be caused because the name you selected for your cloud9 environment is different from karpenter-workshop. You can either find out and replace the name in the commands with the right name or Use the console to delete the environment.