NASA doesn't offer WiFi services like a typical internet provider. The space agency uses a complex network infrastructure for communication and data transmission. While NASA uses various communication technologies, including satellite links and ground stations, it's not something you can sign up for like a regular internet plan.
The cost of maintaining NASA's communication infrastructure is factored into the agency's overall budget, which comes from the US government. Therefore, it's not possible to assign a specific cost to "NASA WiFi" as it's not a separate service.