I don’t have that much data stored on Wasabi, but my understanding is that there is a base cost per month of $4.99 since there is a 1 TB minimum to cover their costs per customer. Short-lived objects will be more expensive on Wasabi, as every object is billed as if it had lived for 90 days in storage:
Timed Deleted Storage: This item is associated with the amount of deleted storage that has not yet reached the 90-day minimum storage charge with Wasabi for the billing cycle. Wasabi charges a minimum of 90 days for any storage object (active or deleted). This policy is comparable to the minimum storage charge period applicable to some of Amazon’s object storage services. The unit price for timed deleted storage is the same as the unit price for timed active storage. As an example, if you store an object with Wasabi for 15 days and then delete it, you will still be charged for 90 days of storage (15 days of timed active storage and 75 days of timed deleted storage). The storage charges for this simple example will be spread over three sequential 30-day billing cycles in a manner that looks like this:
First 30-day billing cycle: 15 days of timed active storage + 15 days of timed deleted storage
Second 30-day billing cycle: 30 days of timed deleted storage
Third 30-day billing cycle: 30 days of timed deleted storage
My really inexperienced guess is that, considering your volume, as long as your data is there more than 90 days, it will be a good value.