Backblaze B2 is another option. Not sure if its as cheap as Glacier as its hard to compare usage based billing.
I pay about $1-2 USD/mo for 100GB. Storage is about $0.02/day, The rest of the cost is access costs.
I use rclone to do my own encryption. Most of the cost is probably backing up my phone nightly (Round Sync which is rclone on Android). Specifically signal results in a new 400Mb backup every night with 99% of the same data as the last backup.