It's not nearly as cheap as Glacier, but Backblaze's B2 is $5/TB (and $10/TB to download), putting it between S3 and Glacier. I don't know if the upload speed to B2 is capped; my internet isn't fast enough to tell.

That might be prohibitive if you have a huge NAS to back up, but for moderately large amounts of data (say 5 TBs or less), it seems pretty reasonable.