According to their documentation, Wasabi will move you on to their $0.005/GB storage $0.01/GB download plan (same price as B2 without api charges) from their $0.0059/GB storage free egress plan if you download more than your total storage (eg. with 100TB stored don't download more than 100TB/month).
elabajaba|6 years ago
https://wasabi.com/pricing/pricing-faqs/