Signing up for Wasabi resulted in a deluge of unwanted marketing spam, all written to be "cheerful and your friend"

Also, huge warning for Wasabi newbies so you are not surprised. This might wreck your wallet.

Your egress is capped at your total amount stored. You cannot store 5TB and have 6TB of downloads against that account. The front page is covered in 'No Charges For Egress' 'no additional charges for egress or API requests'.. etc. This is not written anywhere on the main marketing pages, only behind a small link.

Another important point is file deletion. You are required to pay for multiple billing cycles (months) of files. Be very cautious about this. Using it as a temporary bucket will incur significant costs, if you upload a file, YOU WILL PAY FOR 90 DAYS OF THAT FILE. It is almost certainly not cost effective to store files in Wasabi any less than long term. Deleting a file that you just uploaded will incur a deletion fee equivalent to 3 months of storing that file.

One thing people should bear in mind when looking at Wasabi is that they have a 90 day minimum retention period for their PAYG plans. So if you upload a large file and overwrite it tomorrow, you'll be charged the storage fee for the day plus the storage fee for the remaining 89 days, and then the storage fee for the new file, and so on.

The same goes for AWS IA and Glacier classes and Google's Nearline and Coldline. Unless you're storing files for a long time, always factor in the minimum retention period before estimating costs. It'll prevent any nasty billing surprises -- speaking from experience unfortunately.