If compression is purely a function of the price, things are not so obvious. I think Backblaze B2 is the cheapest, but it's not supported by Borg. So a backup

If compression is purely a function of the price, things are not so obvious. I think Backblaze B2 is the cheapest, but it's not supported by Borg. So a backup system without compression support, but with B2 support, may ultimately be cheaper than a system with opposite features. It's also important to consider the use case. If a user's bulk of data is photos/videos/audio files, there's virtually no use of compression - but of course, the proportion will vary per user.