I have a fairly optimized backup to glacier strategy involving a couple of days of soak time in S3 before moving to glacier with lifecycle rules to avoid the 180 day min storage for transient files. Net I end up paying about $1.20 to $1.50 per TB per month. Restoration of my data set would cost around $100/TB though. So a straight $1/TB would be a nice savings on a good month, and a great savings if my house ever burns down and I need to restore.