AWS has released an even more cost effective storate tier called Glacier Deep Archive that offers ~12 hour retrieval latencies, but costs roughly a thousand dollars per month per petabyte.
You can physically ship your data to Amazon to put on Glacier on a USB or eSATA HDD.
Glacier Gotchas and Limitations
🔸Getting files off Glacier is glacially slow (typically 3-5 hours or more).
🔸Due to a fixed overhead per file (you pay per PUT or GET operation), uploading and downloading many small files on/to Glacier might be very expensive. There is also a 32k storage overhead per file. Hence it’s a good idea is to archive files before upload.