Yeah their descriptions are pretty confusing. I think it’s 75GB total storage.
“75 GB Free Every Month
You get 75GB of free storage and external outgoing transfer on both Object Storage and C14 Cold Storage every month! For Object Storage’s Standard Class, the price charged above these 75 GB is €0.01/GB per month per volume stored, and €0.01/GB per volume transferred. In addition, transfer to and from other Scaleway products in the same region are completely free! You also don’t have any fees per API or console request. Your invoice is clear and without surprises.”