A recurring assumption in SaaS is that lower compute costs should permit lower subscription prices. That only follows when compute is a meaningful share of total cost.
For many products the expensive layers are acquisition, support, compliance, payment processing, fraud, taxes and continuous product work. At a very low monthly price, fixed transaction and support costs can matter more than hosting.
That creates an odd market: software may be cheaper to build while small subscriptions remain structurally difficult. The durable low-price products are likely to be the ones with unusually strong organic distribution and very low support intensity.