I have about 150GB in /home backed up daily using Duplicity, which encrypts & compresses everything and saves to a second internal backup drive. Data is kept for 6 months minimum. After several years, the total backup size is 190GB which syncs daily to an S3 bucket and my monthly bills are about $11USD. If I ever had to restore all that from S3 it would cost extra but would not be prohibitively expensive.

Install the AWS CLI (https://aws.amazon.com/cli/) and choose whatever method you like for making an encrypted local backup. Then sync that backup partition to S3 every day.

Here's an example command you can adapt for cron to call via a shell script:

    /home/tom/.local/bin/aws s3 sync /mnt/backups/daily s3://your-s3-bucket-name --storage-class STANDARD_IA --acl private --sse

The -sse means server side encryption which is redundant since I've encrypted the data prior to uploading, but why not?