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.

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 delete aws-node-termination-handler --namespace kube-system
helm delete karpenter --namespace karpenter
helm delete kube-ops-view
kubectl delete -f

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

aws cloudformation delete-stack --stack-name Karpenter-eksworkshop-eksctl
eksctl delete cluster -f eksworkshop.yaml

Delete SSH Key Pair and Cloud 9

aws ec2 delete-key-pair --key-name eksworkshop
CLOUD_9_IDS=$(aws cloud9 list-environments | jq -c ".environmentIds | flatten(0)" | sed -E -e 's/\[|\]|\"|//g' | sed 's/,/ /g')
CLOUD_9_WORKSHOP_ID=$(aws cloud9 describe-environments --environment-ids $CLOUD_9_IDS | jq '.environments | .[] | select(.name=="eksworkshop") | .id ' | sed -e 's/\"//g')
aws cloud9 delete-environment --environment-id $CLOUD_9_WORKSHOP_ID

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 eksworkshop. You can either find out and replace the name in the commands with the right name or Use the console to delete the environment.