[maxwelldone]

Glacier Deep is the cheapest option. It does come with a catch that there's a minimum of 180 days commitment for their infrequent access tier. Last time I checked, the cost for US-East-1 is roughly like this:

At $0.00099/GB/month, it would cost ~$12/year to store 1TB. Retrieval cost is $0.0025/GB and bandwidth down is $0.09/GB (exorbitant! But you get 100GB/mo free)

So, retrieving 1TB (924GB chargeable) once will run ~$85. I've also excluded their http request pricing which shouldn't matter much unless you've millions of objects.

For the same amount of data, Backblaze costs ~$60/year to store but only $10 to retrieve (at $0.01/GB).

I suppose an important factor to consider in archival storage is the expected number of retrievals, and whether you can handle the cost.