Wasabi prices are kind of incredible, IMO and I have not seen cheaper options. B2 also has the aspect that download costs money. So if you want to restore 150GB, this costs $1.5.
Only option that is comparable is probably Hetzner storage box. 1TB is around $9. This solution is only practical if your server is somewhere near their storage box.
(Ignoring the cheapest option of buying a external hard disk and attaching it to your physical server I bought a 2TB disk for just $55. The disk will pay for itself in 8 months of cloud storage)
@marcusquinn Great summary! I've similarly found that ingress transaction costs are more than my monthly storage costs with rsync option and tar zip backups keep timing out.
@girish Thanks for adding the additional advanced backup configuration in 5.5! I've tried increasing it for my backups and am excited to see if it helps.